diff --git a/README.md b/README.md
index ccaeffe..25322f2 100644
--- a/README.md
+++ b/README.md
@@ -142,7 +142,7 @@ Flags:
   -h, --help                              Show context-sensitive help.
       --function=STRING                   Function file path ($LAMBROLL_FUNCTION)
       --log-level="info"                  log level (trace, debug, info, warn, error) ($LAMBROLL_LOGLEVEL)
-      --color                             enable colored output ($LAMBROLL_COLOR)
+      --[no-]color                        enable colored output ($LAMBROLL_COLOR)
       --region=REGION                     AWS region ($AWS_REGION)
       --profile=PROFILE                   AWS credential profile name ($AWS_PROFILE)
       --tfstate=TFSTATE                   URL to terraform.tfstate ($LAMBROLL_TFSTATE)
diff --git a/cli.go b/cli.go
index d576fa6..0c1543f 100644
--- a/cli.go
+++ b/cli.go
@@ -15,7 +15,7 @@ import (
 type Option struct {
 	Function string `help:"Function file path" env:"LAMBROLL_FUNCTION"`
 	LogLevel string `help:"log level (trace, debug, info, warn, error)" default:"info" enum:"trace,debug,info,warn,error" env:"LAMBROLL_LOGLEVEL"`
-	Color    bool   `help:"enable colored output" default:"true" env:"LAMBROLL_COLOR"`
+	Color    bool   `help:"enable colored output" default:"true" env:"LAMBROLL_COLOR" negatable:""`
 
 	Region          *string           `help:"AWS region" env:"AWS_REGION"`
 	Profile         *string           `help:"AWS credential profile name" env:"AWS_PROFILE"`