diff --git a/runtime/syntax/sh.vim b/runtime/syntax/sh.vim
index 4add7921f3..c04b16fa0e 100644
--- a/runtime/syntax/sh.vim
+++ b/runtime/syntax/sh.vim
@@ -12,6 +12,7 @@
 "		2025 Apr 10 improve shell detection (#17084)
 "		2025 Apr 29 match escaped chars in test operands (#17221)
 "		2025 May 06 improve single-quote string matching in parameter expansions
+"		2025 May 06 match KornShell compound arrays
 " Version:		208
 " Former URL:		http://www.drchip.org/astronaut/vim/index.html#SYNTAX_SH
 " For options and settings, please use:      :help ft-sh-syntax
@@ -511,13 +512,18 @@ syn match  shSetOption	"\s\zs[-+][a-zA-Z0-9]\+\>"	contained
 syn match  shVariable	"\<\h\w*\ze="			nextgroup=shVarAssign
 if exists("b:is_bash")
  " The subscript form for array values, e.g. "foo=([2]=10 [4]=100)".
- syn region shArrayValue	contained	start="\[\%(..\{-}\]=\)\@=" end="\]=\@="	contains=@shArrayValueList nextgroup=shVarAssign
+ syn region  shArrayValue	contained	start="\[\%(..\{-}\]=\)\@=" end="\]=\@="	contains=@shArrayValueList nextgroup=shVarAssign
  syn cluster shArrayValueList	contains=shArithmetic,shArithParen,shCommandSub,shDeref,shDerefSimple,shExpr,shNumber,shExSingleQuote,shExDoubleQuote,shSingleQuote,shDoubleQuote,shSpecial,shParen,bashSpecialVariables,shParenError
+ syn region  shArrayRegion	contained matchgroup=shShellVariables start="(" skip='\\\\\|\\.' end=")" contains=@shArrayValueList,shArrayValue,shComment
+elseif exists("b:is_kornshell")
+ " The subscript form for array values, e.g. "foo=([2]=10 [4]=100)".
+ syn region  shArrayValue	contained	start="\[\%(..\{-}\]=\)\@=" end="\]=\@="	contains=@shArrayValueList nextgroup=shVarAssign
+ syn cluster shArrayValueList	contains=shArithmetic,shArithParen,shCommandSub,shDeref,shDerefSimple,shExpr,shNumber,shExSingleQuote,shExDoubleQuote,shSingleQuote,shDoubleQuote,shSpecial,shParen,kshSpecialVariables,shParenError
+ syn region  shArrayRegion	contained matchgroup=shShellVariables start="(" skip='\\\\\|\\.' end=")" contains=@shArrayValueList,shArrayValue,shComment,shArrayRegion
 endif
 if exists("b:is_bash") || exists("b:is_kornshell")
  syn match shVariable	"\<\h\w*\%(\[..\{-}\]\)\=\ze\%([|^&*/%+-]\|[<^]<\|[>^]>\)\=="	contains=shDerefVarArray nextgroup=shVarAssign
  syn match shVarAssign	contained	"\%([|^&*/%+-]\|[<^]<\|[>^]>\)\=="	nextgroup=shArrayRegion,shPattern,shDeref,shDerefSimple,shDoubleQuote,shExDoubleQuote,shSingleQuote,shExSingleQuote,shVar
- syn region shArrayRegion	contained matchgroup=shShellVariables start="(" skip='\\\\\|\\.' end=")" contains=@shArrayValueList,shArrayValue,shComment
 else
  syn match  shVarAssign	contained	"="	nextgroup=shPattern,shDeref,shDerefSimple,shDoubleQuote,shExDoubleQuote,shSingleQuote,shExSingleQuote,shVar
 endif
diff --git a/runtime/syntax/testdir/dumps/sh_ksh_array_00.dump b/runtime/syntax/testdir/dumps/sh_ksh_array_00.dump
new file mode 100644
index 0000000000..7d3855dc6c
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/sh_ksh_array_00.dump
@@ -0,0 +1,20 @@
+>#+0#0000e05#ffffff0|!|/|b|i|n|/|k|s|h| +0#0000000&@64
+@75
+|f+0#00e0e07&|o@1|=+0#0000000&|(+0#e000e06&| +0#0000000&@69
+@2|(+0#e000e06&| |0+0#e000002&@1| +0#e000e06&|0+0#e000002&|1| +0#e000e06&|)| +0#0000000&@63
+@2|(+0#e000e06&| |1+0#e000002&|0| +0#e000e06&|1+0#e000002&@1| +0#e000e06&|)| +0#0000000&@63
+|)+0#e000e06&| +0#0000000&@73
+@75
+|b+0#00e0e07&|a|r|=+0#0000000&|(+0#e000e06&| +0#0000000&@69
+@2|[+0#e000e06&|0+0#e000002&|]+0#e000e06&|=+0#0000000&|(+0#e000e06&| +0#0000000&@67
+@4|[+0#e000e06&|0+0#e000002&|]+0#e000e06&|=+0#0000000&|0+0#e000002&@1| +0#0000000&@64
+@4|[+0#e000e06&|1+0#e000002&|]+0#e000e06&|=+0#0000000&|0+0#e000002&|1| +0#0000000&@64
+@2|)+0#e000e06&| +0#0000000&@71
+@2|[+0#e000e06&|1+0#e000002&|]+0#e000e06&|=+0#0000000&|(+0#e000e06&| +0#0000000&@67
+@4|[+0#e000e06&|0+0#e000002&|]+0#e000e06&|=+0#0000000&|1+0#e000002&|0| +0#0000000&@64
+@4|[+0#e000e06&|1+0#e000002&|]+0#e000e06&|=+0#0000000&|1+0#e000002&@1| +0#0000000&@64
+@2|)+0#e000e06&| +0#0000000&@71
+|)+0#e000e06&| +0#0000000&@73
+@75
+@75
+|i|s|_|k|o|r|n|s|h|e|l@1|:| |1|,| @40|1|,|1| @10|T|o|p| 
diff --git a/runtime/syntax/testdir/dumps/sh_ksh_array_01.dump b/runtime/syntax/testdir/dumps/sh_ksh_array_01.dump
new file mode 100644
index 0000000000..af895cfcf4
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/sh_ksh_array_01.dump
@@ -0,0 +1,20 @@
+| +0&#ffffff0@3|[+0#e000e06&|0+0#e000002&|]+0#e000e06&|=+0#0000000&|1+0#e000002&|0| +0#0000000&@64
+@4|[+0#e000e06&|1+0#e000002&|]+0#e000e06&|=+0#0000000&|1+0#e000002&@1| +0#0000000&@64
+@2|)+0#e000e06&| +0#0000000&@71
+|)+0#e000e06&| +0#0000000&@73
+@75
+> @74
+|e+0#af5f00255&|c|h|o| +0#e000002&|$+0#e000e06&|{|f|o@1|[|1+0#e000002&|]+0#e000e06&|[|1+0#e000002&|]+0#e000e06&|}| +0#e000002&|#+0#0000e05&| |=|>| |1@1| +0#0000000&@49
+|e+0#af5f00255&|c|h|o| +0#e000002&|$+0#e000e06&|{|b|a|r|[|1+0#e000002&|]+0#e000e06&|[|1+0#e000002&|]+0#e000e06&|}| +0#e000002&|#+0#0000e05&| |=|>| |1@1| +0#0000000&@49
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|9|,|0|-|1| @7|B|o|t| 
diff --git a/runtime/syntax/testdir/input/sh_ksh_array.sh b/runtime/syntax/testdir/input/sh_ksh_array.sh
new file mode 100755
index 0000000000..22806ffc5c
--- /dev/null
+++ b/runtime/syntax/testdir/input/sh_ksh_array.sh
@@ -0,0 +1,21 @@
+#!/bin/ksh
+
+foo=(
+  ( 00 01 )
+  ( 10 11 )
+)
+
+bar=(
+  [0]=(
+    [0]=00
+    [1]=01
+  )
+  [1]=(
+    [0]=10
+    [1]=11
+  )
+)
+
+
+echo ${foo[1][1]} # => 11
+echo ${bar[1][1]} # => 11