diff --git a/icu4c/source/common/uloc.cpp b/icu4c/source/common/uloc.cpp
index 73b43204b814..2c1122db842c 100644
--- a/icu4c/source/common/uloc.cpp
+++ b/icu4c/source/common/uloc.cpp
@@ -464,6 +464,8 @@ typedef struct CanonicalizationMap {
  * different semantic kinds of transformations.
  */
 static const CanonicalizationMap CANONICALIZE_MAP[] = {
+    { "c",              "en_US_POSIX" }, /* POSIX name */
+    { "posix",          "en_US_POSIX" }, /* POSIX name (alias of C) */
     { "art_LOJBAN",     "jbo" }, /* registered name */
     { "hy__AREVELA",    "hy" }, /* Registered IANA variant */
     { "hy__AREVMDA",    "hyw" }, /* Registered IANA variant */