diff --git a/demos/modules/demo_chart.mjs b/demos/modules/demo_chart.mjs
index ec30763db..5059c0052 100644
--- a/demos/modules/demo_chart.mjs
+++ b/demos/modules/demo_chart.mjs
@@ -63,6 +63,8 @@ export function genSlides_Chart(pptx) {
 	genSlide16(pptx);
 	genSlide17(pptx);
 	genSlide18(pptx);
+	genSlide19(pptx);
+	genSlide20(pptx);
 }
 
 function initTestData() {
@@ -1642,9 +1644,6 @@ function genSlide16(pptx) {
 
 // SLIDE 17: Multi-Type Charts
 function genSlide17(pptx) {
-	// powerpoint 2016 add secondary category axis labels
-	// https://peltiertech.com/chart-with-a-dual-category-axis/
-
 	let slide = pptx.addSlide({ sectionTitle: "Charts" });
 	slide.addNotes("API Docs: https://gitbrent.github.io/PptxGenJS/docs/api-charts.html");
 	slide.addTable([[{ text: "Chart Examples: Multi-Type Charts", options: BASE_TEXT_OPTS_L }, BASE_TEXT_OPTS_R]], BASE_TABLE_OPTS);
@@ -2200,3 +2199,184 @@ function genSlide18(pptx) {
 	slide.addChart(pptx.charts.BAR, arrDataRegions, optsChartBar3);
 	slide.addChart(pptx.charts.BAR, arrDataHighVals, optsChartBar4);
 }
+
+// SLIDE 19: Chart Examples: Multi Level Category Axes
+function genSlide19(pptx) {
+	let slide = pptx.addSlide({ sectionTitle: "Charts" });
+	slide.addNotes("API Docs: https://gitbrent.github.io/PptxGenJS/docs/api-charts.html");
+	slide.addTable([[{ text: "Chart Examples: Multi Level Category Axes", options: BASE_TEXT_OPTS_L }, BASE_TEXT_OPTS_R]], BASE_TABLE_OPTS);
+
+		const arrDataRegions = [
+			{
+				name: 'Mechanical',
+				labels: [
+					[
+						'Gear',  'Bearing',
+						'Motor', 'Switch',
+						'Plug',  'Cord',
+						'Fuse',  'Bulb',
+						'Pump',  'Leak',
+						'Seals'
+					],
+					[
+						'Mechanical', '',
+						'',           'Electrical',
+						'',           '',
+						'',           '',
+						'Hydraulic',  '',
+						''
+					]
+				],
+				values: [
+					11, 8, 3, 0, 0,
+					 0, 0, 0, 0, 0,
+					 0
+				]
+			},
+			{
+				name: 'Electrical',
+				labels: [
+					[
+						'Gear',  'Bearing',
+						'Motor', 'Switch',
+						'Plug',  'Cord',
+						'Fuse',  'Bulb',
+						'Pump',  'Leak',
+						'Seals'
+					],
+					[
+						'Mechanical', '',
+						'',           'Electrical',
+						'',           '',
+						'',           '',
+						'Hydraulic',  '',
+						''
+					]
+				],
+				values: [
+					 0, 0, 0, 19, 12,
+					11, 3, 2,  0,  0,
+					 0
+				]
+			},
+			{
+				name: 'Hydraulic',
+				labels: [
+					[
+						'Gear',  'Bearing',
+						'Motor', 'Switch',
+						'Plug',  'Cord',
+						'Fuse',  'Bulb',
+						'Pump',  'Leak',
+						'Seals'
+					],
+					[
+						'Mechanical', '',
+						'',           'Electrical',
+						'',           '',
+						'',           '',
+						'Hydraulic',  '',
+						''
+					]
+				],
+				values: [
+					0, 0, 0, 0, 0,
+					0, 0, 0, 4, 3,
+					1
+				]
+			}
+		];
+
+		const opts1 = {
+			catAxisMultiLevelLabels: true,
+			x: 0.6,
+			y: 0.6,
+			w: 6.0,
+			h: 3.0,
+		};
+
+		const opts2 = {
+			barDir: 'col',
+
+			catAxisMultiLevelLabels: true,
+			x: 7.0,
+			y: 0.6,
+			w: 6.0,
+			h: 3.0,
+		};
+
+		const opts3 = {
+			barDir: 'col',
+
+			catAxisMultiLevelLabels: true,
+			x: 0.6,
+			y: 4.0,
+			w: 6.0,
+			h: 3.0,
+		};
+
+		const opts4 = {
+			catAxisMultiLevelLabels: true,
+			x: 7,
+			y: 4.0,
+			w: 6.0,
+			h: 3.0,
+		};
+
+		slide.addChart(pptx.charts.AREA, arrDataRegions, opts1);
+		slide.addChart(pptx.charts.BAR, arrDataRegions, opts2);
+		slide.addChart(pptx.charts.BAR3D, arrDataRegions, opts3);
+		slide.addChart(pptx.charts.LINE, arrDataRegions, opts4);
+}
+
+// SLIDE 20: Chart Examples: Three Levels Category Axes
+function genSlide20(pptx) {
+	let slide = pptx.addSlide({ sectionTitle: "Charts" });
+	slide.addNotes("API Docs: https://gitbrent.github.io/PptxGenJS/docs/api-charts.html");
+	slide.addTable([[{ text: "Chart Examples: Three Levels Category Axes", options: BASE_TEXT_OPTS_L }, BASE_TEXT_OPTS_R]], BASE_TABLE_OPTS);
+
+	const arrDataRegions = [
+		{
+		  name: 'Fruits',
+		  labels: [
+			[
+			  '1/3',  '1/25', '6/5',
+			  '6/21', '7/27', '2/20',
+			  '3/17', '4/24', '6/23',
+			  '8/5',  '4/16', '1/29',
+			  '2/23', '4/4',  '7/15'
+			],
+			[
+			  'Apple', '', '',
+			  '',      '', 'Orange',
+			  '',      '', '',
+			  'Orange',      '', 'Peach',
+			  'Pear',  '', '',
+			  ''
+			],
+			[
+			  '2014', '',     '', '',
+			  '',     '',     '', '',
+			  '',     '2015', '', '',
+			  '',     '',     '', ''
+			]
+		  ],
+		  values: [
+			734, 465, 656, 176,
+			434, 165, 613, 359,
+			279, 660, 307, 270,
+			539, 142, 554
+		  ]
+		}
+	  ];
+
+	const opts1 = {
+		catAxisMultiLevelLabels: true,
+		x: 0.2,
+		y: 0.2,
+		w: 12.9,
+		h: 7.1
+	};
+
+	slide.addChart(pptx.charts.BAR, arrDataRegions, opts1);
+}
diff --git a/src/core-interfaces.ts b/src/core-interfaces.ts
index 215d470c6..f18a69200 100644
--- a/src/core-interfaces.ts
+++ b/src/core-interfaces.ts
@@ -1107,7 +1107,7 @@ export interface OptsDataLabelPosition {
 export type ChartAxisTickMark = 'none' | 'inside' | 'outside' | 'cross'
 export interface OptsChartData {
 	index?: number
-	labels?: string[]
+	labels?: string[] | string[][]
 	name?: string
 	sizes?: number[]
 	values?: number[]
@@ -1116,6 +1116,10 @@ export interface OptsChartData {
 	 */
 	//color?: string // TODO: WIP: (Pull #727)
 }
+// Used internally, probably shouldn't be used by end users
+export interface IOptsChartData extends OptsChartData {
+	labels?: string[][]
+}
 export interface OptsChartGridLine {
 	/**
 	 * Gridline color (hex)
@@ -1231,6 +1235,7 @@ export interface IChartPropsAxisCat {
 	catAxisMinorTimeUnit?: string
 	catAxisMinorUnit?: string
 	catAxisMinVal?: number
+	catAxisMultiLevelLabels?: boolean
 	catAxisOrientation?: 'minMax'
 	catAxisTitle?: string
 	catAxisTitleColor?: string
@@ -1490,7 +1495,7 @@ export interface IChartOptsLib extends IChartOpts {
 export interface ISlideRelChart extends OptsChartData {
 	type: CHART_NAME | IChartMulti[]
 	opts: IChartOptsLib
-	data: OptsChartData[]
+	data: IOptsChartData[]
 	// internal below
 	rId: number
 	Target: string
diff --git a/src/gen-charts.ts b/src/gen-charts.ts
index c1663d245..c41aa65fe 100644
--- a/src/gen-charts.ts
+++ b/src/gen-charts.ts
@@ -19,7 +19,7 @@ import {
 	LETTERS,
 	ONEPT,
 } from './core-enums'
-import { IChartOptsLib, ISlideRelChart, ShadowProps, OptsChartData, IChartPropsTitle, OptsChartGridLine } from './core-interfaces'
+import { IChartOptsLib, ISlideRelChart, ShadowProps, IChartPropsTitle, OptsChartGridLine, IOptsChartData } from './core-interfaces'
 import { createColorElement, genXmlColorSelection, convertRotationDegrees, encodeXmlEntities, getMix, getUuid, valToPts } from './gen-utils'
 import JSZip from 'jszip'
 
@@ -146,13 +146,18 @@ export function createExcelWorksheet(chartObject: ISlideRelChart, zip: JSZip): P
 				strSharedStrings +=
 					'<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="' + (data.length + 1) + '" uniqueCount="' + (data.length + 1) + '">'
 			} else {
+				// series names + all labels of one series + number of label groups (data.labels.length) of one series (i.e. how many times the blank string is used)
+				const count       = data.length + data[0].labels.length * data[0].labels[0].length + data[0].labels.length
+				// series names + labels of one series + blank string (same for all label groups)
+				const uniqueCount = data.length + data[0].labels.length * data[0].labels[0].length + 1
+
 				strSharedStrings +=
 					'<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="' +
-					(data[0].labels.length + data.length + 1) +
+					(count) +
 					'" uniqueCount="' +
-					(data[0].labels.length + data.length + 1) +
+					(uniqueCount) +
 					'">'
-				// B: Add 'blank' for A1
+				// B: Add 'blank' for A1, B1, ..., of every label group inside data[n].labels
 				strSharedStrings += '<si><t xml:space="preserve"></t></si>'
 			}
 
@@ -173,8 +178,10 @@ export function createExcelWorksheet(chartObject: ISlideRelChart, zip: JSZip): P
 
 			// D: Add `labels`/Categories
 			if (chartObject.opts._type !== CHART_TYPE.BUBBLE && chartObject.opts._type !== CHART_TYPE.BUBBLE3D && chartObject.opts._type !== CHART_TYPE.SCATTER) {
-				data[0].labels.forEach(label => {
-					strSharedStrings += '<si><t>' + encodeXmlEntities(label) + '</t></si>'
+				data[0].labels.forEach(labelsGroup => {
+					labelsGroup.forEach(label => {
+						strSharedStrings += '<si><t>' + encodeXmlEntities(label) + '</t></si>'
+					})
 				})
 			}
 
@@ -204,13 +211,15 @@ export function createExcelWorksheet(chartObject: ISlideRelChart, zip: JSZip): P
 			} else {
 				strTableXml +=
 					'<table xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" id="1" name="Table1" displayName="Table1" ref="A1:' +
-					LETTERS[data.length] +
-					(data[0].labels.length + 1) +
+					getExcelColName(data.length + data[0].labels.length - 1) +
+					(data[0].labels[0].length + 1) +
 					'" totalsRowShown="0">'
-				strTableXml += '<tableColumns count="' + (data.length + 1) + '">'
-				strTableXml += '<tableColumn id="1" name=" " />'
+				strTableXml += '<tableColumns count="' + (data.length + data[0].labels.length) + '">'
+				data[0].labels.forEach((_labelsGroup, idx) => {
+					strTableXml += '<tableColumn id="'+ (idx + 1) + '" name=" " />'
+				})
 				data.forEach((obj, idx) => {
-					strTableXml += '<tableColumn id="' + (idx + 2) + '" name="' + encodeXmlEntities(obj.name) + '" />'
+					strTableXml += '<tableColumn id="' + (idx + data[0].labels.length + 1) + '" name="' + encodeXmlEntities(obj.name) + '" />'
 				})
 			}
 			strTableXml += '</tableColumns>'
@@ -229,7 +238,7 @@ export function createExcelWorksheet(chartObject: ISlideRelChart, zip: JSZip): P
 			} else if (chartObject.opts._type === CHART_TYPE.SCATTER) {
 				strSheetXml += '<dimension ref="A1:' + LETTERS[data.length - 1] + (data[0].values.length + 1) + '" />'
 			} else {
-				strSheetXml += '<dimension ref="A1:' + LETTERS[data.length] + (data[0].labels.length + 1) + '" />'
+				strSheetXml += '<dimension ref="A1:' + LETTERS[data.length + data[0].labels.length - 1] + (data[0].labels.length + 1) + '" />'
 			}
 
 			strSheetXml += '<sheetViews><sheetView tabSelected="1" workbookViewId="0"><selection activeCell="B1" sqref="B1" /></sheetView></sheetViews>'
@@ -352,26 +361,33 @@ export function createExcelWorksheet(chartObject: ISlideRelChart, zip: JSZip): P
 					-|-------|-----|-----|-----|
 				*/
 
-				// A: Create header row first (NOTE: Start at index=1 as headers cols start with 'B')
-				strSheetXml += '<row r="1" spans="1:' + (data.length + 1) + '">'
-				strSheetXml += '<c r="A1" t="s"><v>0</v></c>'
+				// A: Create header row first
+				strSheetXml += '<row r="1" spans="1:' + (data.length + data[0].labels.length) + '">'
+				data[0].labels.forEach((_labelsGroup, idx) => {
+					strSheetXml += '<c r="' + getExcelColName(idx) + '1" t="s">'
+					strSheetXml += '<v>0</v>'
+					strSheetXml += '</c>'
+				})
 				for (let idx = 1; idx <= data.length; idx++) {
 					// FIXME: Max cols is 52
-					strSheetXml += '<c r="' + (idx < 26 ? LETTERS[idx] : 'A' + LETTERS[idx % LETTERS.length]) + '1" t="s">' // NOTE: use `t="s"` for label cols!
+					strSheetXml += '<c r="' + getExcelColName(idx + data[0].labels.length - 1) + '1" t="s">' // NOTE: use `t="s"` for label cols!
 					strSheetXml += '<v>' + idx + '</v>'
 					strSheetXml += '</c>'
 				}
 				strSheetXml += '</row>'
 
 				// B: Add data row(s) for each category
-				data[0].labels.forEach((_cat, idx) => {
-					// Leading col is reserved for the label, so hard-code it, then loop over col values
-					strSheetXml += '<row r="' + (idx + 2) + '" spans="1:' + (data.length + 1) + '">'
-					strSheetXml += '<c r="A' + (idx + 2) + '" t="s">'
-					strSheetXml += '<v>' + (data.length + idx + 1) + '</v>'
-					strSheetXml += '</c>'
+				data[0].labels[0].forEach((_cat, idx) => {
+					strSheetXml += '<row r="' + (idx + 2) + '" spans="1:' + (data.length + data[0].labels.length) + '">'
+					// Leading cols are reserved for the label groups
+					for (let idx2 = data[0].labels.length - 1; idx2 >= 0; idx2--) {
+						strSheetXml += '<c r="' + getExcelColName(data[0].labels.length - 1 - idx2) + '' + (idx + 2) + '" t="s">'
+						strSheetXml += '<v>' + (data.length + idx + (idx2 * (data[0].labels[0].length)) + 1) + '</v>'
+						strSheetXml += '</c>'
+					}
+
 					for (let idy = 0; idy < data.length; idy++) {
-						strSheetXml += '<c r="' + (idy + 1 < 26 ? LETTERS[idy + 1] : 'A' + LETTERS[(idy + 1) % LETTERS.length]) + '' + (idx + 2) + '">'
+						strSheetXml += '<c r="' + getExcelColName(idy + data[0].labels.length) + '' + (idx + 2) + '">'
 						strSheetXml += '<v>' + (data[idy].values[idx] || '') + '</v>'
 						strSheetXml += '</c>'
 					}
@@ -645,7 +661,7 @@ export function makeXmlCharts(rel: ISlideRelChart): string {
  * @example '<c:lineChart>'
  * @return {string} XML
  */
-function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChartOptsLib, valAxisId: string, catAxisId: string, isMultiTypeChart: boolean): string {
+function makeChartType(chartType: CHART_NAME, data: IOptsChartData[], opts: IChartOptsLib, valAxisId: string, catAxisId: string, isMultiTypeChart: boolean): string {
 	// NOTE: "Chart Range" (as shown in "select Chart Area dialog") is calculated.
 	// ....: Ensure each X/Y Axis/Col has same row height (esp. applicable to XY Scatter where X can often be larger than Y's)
 	let strXml: string = ''
@@ -674,20 +690,40 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 			strXml += '<c:varyColors val="0"/>'
 
 			// 2: "Series" block for every data row
-			/* EX:
+			/* EX1:
 				data: [
 				 {
 				   name: 'Region 1',
-				   labels: ['April', 'May', 'June', 'July'],
+				   labels: [['April', 'May', 'June', 'July']],
 				   values: [17, 26, 53, 96]
 				 },
 				 {
 				   name: 'Region 2',
-				   labels: ['April', 'May', 'June', 'July'],
+				   labels: [['April', 'May', 'June', 'July']],
 				   values: [55, 43, 70, 58]
 				 }
 				]
 			*/
+			/* EX2:
+				data: [
+				 {
+				   name: 'Region 1',
+				   labels: [
+					   ['April', 'May', 'June', 'April', 'May', 'June'],
+					   ['2020',     '',     '', '2021',     '',     '']
+				   ],
+				   values: [17, 26, 53, 96, 40, 33]
+				 },
+				 {
+				   name: 'Region 2',
+				   labels: [
+					   ['April', 'May', 'June', 'April', 'May', 'June'],
+					   ['2020',     '',     '', '2021',     '',     '']
+				   ],
+				   values: [55, 43, 70, 58, 78, 63]
+				 }
+				]
+			 */
 			let colorIndex = -1 // Maintain the color index by region
 			data.forEach(obj => {
 				colorIndex++
@@ -697,7 +733,7 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 				strXml += '  <c:order val="' + idx + '"/>'
 				strXml += '  <c:tx>'
 				strXml += '    <c:strRef>'
-				strXml += '      <c:f>Sheet1!$' + getExcelColName(idx + 1) + '$1</c:f>'
+				strXml += '      <c:f>Sheet1!$' + getExcelColName(idx + obj.labels.length) + '$1</c:f>'
 				strXml += '      <c:strCache><c:ptCount val="1"/><c:pt idx="0"><c:v>' + encodeXmlEntities(obj.name) + '</c:v></c:pt></c:strCache>'
 				strXml += '    </c:strRef>'
 				strXml += '  </c:tx>'
@@ -842,25 +878,29 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 					if (opts.catLabelFormatCode) {
 						// Use 'numRef' as catLabelFormatCode implies that we are expecting numbers here
 						strXml += '  <c:numRef>'
-						strXml += '    <c:f>Sheet1!$A$2:$A$' + (obj.labels.length + 1) + '</c:f>'
+						strXml += '    <c:f>Sheet1!$A$2:$A$' + (obj.labels[0].length + 1) + '</c:f>'
 						strXml += '    <c:numCache>'
 						strXml += '      <c:formatCode>' + (opts.catLabelFormatCode || 'General') + '</c:formatCode>'
-						strXml += '      <c:ptCount val="' + obj.labels.length + '"/>'
-						obj.labels.forEach((label, idx) => {
+						strXml += '      <c:ptCount val="' + obj.labels[0].length + '"/>'
+						obj.labels[0].forEach((label, idx) => {
 							strXml += '<c:pt idx="' + idx + '"><c:v>' + encodeXmlEntities(label) + '</c:v></c:pt>'
 						})
 						strXml += '    </c:numCache>'
 						strXml += '  </c:numRef>'
 					} else {
-						strXml += '  <c:strRef>'
-						strXml += '    <c:f>Sheet1!$A$2:$A$' + (obj.labels.length + 1) + '</c:f>'
-						strXml += '    <c:strCache>'
-						strXml += '	     <c:ptCount val="' + obj.labels.length + '"/>'
-						obj.labels.forEach((label, idx) => {
-							strXml += '<c:pt idx="' + idx + '"><c:v>' + encodeXmlEntities(label) + '</c:v></c:pt>'
+						strXml += '  <c:multiLvlStrRef>'
+						strXml += '    <c:f>Sheet1!$A$2:$' + getExcelColName(obj.labels.length - 1) + '$' + (obj.labels[0].length + 1) + '</c:f>'
+						strXml += '    <c:multiLvlStrCache>'
+						strXml += '	     <c:ptCount val="' + obj.labels[0].length + '"/>'
+						obj.labels.forEach(labelsGroup => {
+							strXml += '  <c:lvl>'
+							labelsGroup.forEach((label, idx) => {
+								strXml += '<c:pt idx="' + idx + '"><c:v>' + encodeXmlEntities(label) + '</c:v></c:pt>'
+							})
+							strXml += '  </c:lvl>'
 						})
-						strXml += '    </c:strCache>'
-						strXml += '  </c:strRef>'
+						strXml += '    </c:multiLvlStrCache>'
+						strXml += '  </c:multiLvlStrRef>'
 					}
 					strXml += '</c:cat>'
 				}
@@ -869,10 +909,10 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 				{
 					strXml += '<c:val>'
 					strXml += '  <c:numRef>'
-					strXml += '    <c:f>Sheet1!$' + getExcelColName(idx + 1) + '$2:$' + getExcelColName(idx + 1) + '$' + (obj.labels.length + 1) + '</c:f>'
+					strXml += '    <c:f>Sheet1!$' + getExcelColName(idx + obj.labels.length) + '$2:$' + getExcelColName(idx + obj.labels.length) + '$' + (obj.labels[0].length + 1) + '</c:f>'
 					strXml += '    <c:numCache>'
 					strXml += '      <c:formatCode>' + (opts.valLabelFormatCode || opts.dataTableFormatCode || 'General') + '</c:formatCode>'
-					strXml += '      <c:ptCount val="' + obj.labels.length + '"/>'
+					strXml += '      <c:ptCount val="' + obj.labels[0].length + '"/>'
 					obj.values.forEach((value, idx) => {
 						strXml += '<c:pt idx="' + idx + '"><c:v>' + (value || value === 0 ? value : '') + '</c:v></c:pt>'
 					})
@@ -1024,9 +1064,9 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 				// Option: scatter data point labels
 				if (opts.showLabel) {
 					let chartUuid = getUuid('-xxxx-xxxx-xxxx-xxxxxxxxxxxx')
-					if (obj.labels && (opts.dataLabelFormatScatter === 'custom' || opts.dataLabelFormatScatter === 'customXY')) {
+					if (obj.labels[0] && (opts.dataLabelFormatScatter === 'custom' || opts.dataLabelFormatScatter === 'customXY')) {
 						strXml += '<c:dLbls>'
-						obj.labels.forEach((label, idx) => {
+						obj.labels[0].forEach((label, idx) => {
 							if (opts.dataLabelFormatScatter === 'custom' || opts.dataLabelFormatScatter === 'customXY') {
 								strXml += '  <c:dLbl>'
 								strXml += '    <c:idx val="' + idx + '"/>'
@@ -1456,7 +1496,7 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 			//strXml += '<c:explosion val="0"/>'
 
 			// 2: "Data Point" block for every data row
-			obj.labels.forEach((_label, idx) => {
+			obj.labels[0].forEach((_label, idx) => {
 				strXml += '<c:dPt>'
 				strXml += ` <c:idx val="${idx}"/>`
 				strXml += ' <c:bubble3D val="0"/>'
@@ -1476,7 +1516,7 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 
 			// 3: "Data Label" block for every data Label
 			strXml += '<c:dLbls>'
-			obj.labels.forEach((_label, idx) => {
+			obj.labels[0].forEach((_label, idx) => {
 				strXml += '<c:dLbl>'
 				strXml += ` <c:idx val="${idx}"/>`
 				strXml += `  <c:numFmt formatCode="${encodeXmlEntities(opts.dataLabelFormatCode) || 'General'}" sourceLinked="0"/>`
@@ -1525,10 +1565,10 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 			// 2: "Categories"
 			strXml += '<c:cat>'
 			strXml += '  <c:strRef>'
-			strXml += '    <c:f>Sheet1!$A$2:$A$' + (obj.labels.length + 1) + '</c:f>'
+			strXml += '    <c:f>Sheet1!$A$2:$A$' + (obj.labels[0].length + 1) + '</c:f>'
 			strXml += '    <c:strCache>'
-			strXml += '	     <c:ptCount val="' + obj.labels.length + '"/>'
-			obj.labels.forEach((label, idx) => {
+			strXml += '	     <c:ptCount val="' + obj.labels[0].length + '"/>'
+			obj.labels[0].forEach((label, idx) => {
 				strXml += '<c:pt idx="' + idx + '"><c:v>' + encodeXmlEntities(label) + '</c:v></c:pt>'
 			})
 			strXml += '    </c:strCache>'
@@ -1538,9 +1578,9 @@ function makeChartType(chartType: CHART_NAME, data: OptsChartData[], opts: IChar
 			// 3: Create vals
 			strXml += '  <c:val>'
 			strXml += '    <c:numRef>'
-			strXml += '      <c:f>Sheet1!$B$2:$B$' + (obj.labels.length + 1) + '</c:f>'
+			strXml += '      <c:f>Sheet1!$B$2:$B$' + (obj.labels[0].length + 1) + '</c:f>'
 			strXml += '      <c:numCache>'
-			strXml += '	       <c:ptCount val="' + obj.labels.length + '"/>'
+			strXml += '	       <c:ptCount val="' + obj.labels[0].length + '"/>'
 			obj.values.forEach((value, idx) => {
 				strXml += '<c:pt idx="' + idx + '"><c:v>' + (value || value === 0 ? value : '') + '</c:v></c:pt>'
 			})
@@ -1646,7 +1686,7 @@ function makeCatAxis(opts: IChartOptsLib, axisId: string, valAxisId: string): st
 	strXml += ` <c:${typeof opts.valAxisCrossesAt === 'number' ? 'crossesAt' : 'crosses'} val="${opts.valAxisCrossesAt || 'autoZero'}"/>`
 	strXml += ' <c:auto val="1"/>'
 	strXml += ' <c:lblAlgn val="ctr"/>'
-	strXml += ' <c:noMultiLvlLbl val="1"/>'
+	strXml += ' <c:noMultiLvlLbl val="' + (opts.catAxisMultiLevelLabels ? 0 : 1) + '"/>'
 	if (opts.catAxisLabelFrequency) strXml += ' <c:tickLblSkip val="' + opts.catAxisLabelFrequency + '"/>'
 
 	// Issue#149: PPT will auto-adjust these as needed after calcing the date bounds, so we only include them when specified by user
diff --git a/src/gen-objects.ts b/src/gen-objects.ts
index 3fbaf2545..b86acfa0c 100644
--- a/src/gen-objects.ts
+++ b/src/gen-objects.ts
@@ -167,6 +167,11 @@ export function addChartDefinition(target: PresSlide, type: CHART_NAME | IChartM
 	}
 	tmpData.forEach((item, i) => {
 		item.index = i
+
+		// Converts the 'labels' array from string[] to string[][] (or the respective primitive type), if needed
+		if (item.labels !== undefined && !Array.isArray(item.labels[0])) {
+			item.labels = [item.labels as string[]]
+		}
 	})
 	options = tmpOpt && typeof tmpOpt === 'object' ? tmpOpt : {}
 
@@ -335,6 +340,12 @@ export function addChartDefinition(target: PresSlide, type: CHART_NAME | IChartM
 	options.lineSize = typeof options.lineSize === 'number' ? options.lineSize : 2
 	options.valAxisMajorUnit = typeof options.valAxisMajorUnit === 'number' ? options.valAxisMajorUnit : null
 
+	if (options._type === CHART_TYPE.AREA || options._type === CHART_TYPE.BAR || options._type === CHART_TYPE.BAR3D || options._type === CHART_TYPE.LINE) {
+		options.catAxisMultiLevelLabels = !!options.catAxisMultiLevelLabels
+	} else {
+		delete options.catAxisMultiLevelLabels
+	}
+
 	// STEP 4: Set props
 	resultObject._type = 'chart'
 	resultObject.options = options
diff --git a/types/index.d.ts b/types/index.d.ts
index 893746e6c..b2ec04def 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -1903,7 +1903,7 @@ declare namespace PptxGenJS {
 	export type ChartAxisTickMark = 'none' | 'inside' | 'outside' | 'cross'
 	export interface OptsChartData {
 		index?: number
-		labels?: string[]
+		labels?: string[] | string[][]
 		name?: string
 		sizes?: number[]
 		values?: number[]