diff --git a/runtime/syntax/chicken.vim b/runtime/syntax/chicken.vim
new file mode 100644
index 0000000..f934d9d
--- /dev/null
+++ b/runtime/syntax/chicken.vim
@@ -0,0 +1,77 @@
+" Vim syntax file
+" Language: Scheme (CHICKEN)
+" Last Change: 2018 Jan 31
+" Author: Evan Hanson <evhan@foldling.org>
+" Maintainer: Evan Hanson <evhan@foldling.org>
+" URL: https://foldling.org/vim/syntax/chicken.vim
+" Notes: This is supplemental syntax, to be loaded after the core Scheme
+" syntax file (syntax/scheme.vim). Enable it by setting b:is_chicken=1
+" and filetype=scheme.
+
+" Only to be used on top of the Scheme syntax.
+if !exists('b:did_scheme_syntax')
+  finish
+endif
+
+" Lighten parentheses.
+hi def link schemeParentheses Comment
+
+" foo#bar
+syn match schemeExtraSyntax /[^ #'`\t\n()\[\]"|;]\+#[^ '`\t\n()\[\]"|;]\+/
+
+" ##foo#bar
+syn match schemeExtraSyntax /##[^ '`\t\n()\[\]"|;]\+/
+
+" Heredocs.
+syn region schemeString start=/#<[<#]\s*\z(.*\)/ end=/^\z1$/
+
+" Keywords.
+syn match schemeKeyword /#[!:][a-zA-Z0-9!$%&*+-./:<=>?@^_~#]\+/
+syn match schemeKeyword /[a-zA-Z0-9!$%&*+-./:<=>?@^_~#]\+:\>/
+
+" C/C++ syntax.
+let s:c = globpath(&rtp, 'syntax/cpp.vim', 0, 1)
+if len(s:c)
+  exe 'syn include @c ' s:c[0]
+  syn region c matchgroup=schemeComment start=/#>/ end=/<#/ contains=@c
+endif
+
+syn keyword schemeSyntax define-record
+
+syn keyword schemeLibrarySyntax declare
+syn keyword schemeLibrarySyntax module
+syn keyword schemeLibrarySyntax reexport
+syn keyword schemeLibrarySyntax require-library
+
+syn keyword schemeTypeSyntax -->
+syn keyword schemeTypeSyntax ->
+syn keyword schemeTypeSyntax :
+syn keyword schemeTypeSyntax assume
+syn keyword schemeTypeSyntax compiler-typecase
+syn keyword schemeTypeSyntax define-specialization
+syn keyword schemeTypeSyntax define-type
+syn keyword schemeTypeSyntax the
+
+syn keyword schemeExtraSyntax and-let*
+syn keyword schemeExtraSyntax match
+syn keyword schemeExtraSyntax match-lambda
+syn keyword schemeExtraSyntax match-lambda*
+
+syn keyword schemeSpecialSyntax define-compiler-syntax
+syn keyword schemeSpecialSyntax define-constant
+syn keyword schemeSpecialSyntax define-external
+syn keyword schemeSpecialSyntax define-inline
+syn keyword schemeSpecialSyntax foreign-code
+syn keyword schemeSpecialSyntax foreign-declare
+syn keyword schemeSpecialSyntax foreign-lambda
+syn keyword schemeSpecialSyntax foreign-lambda*
+syn keyword schemeSpecialSyntax foreign-primitive
+syn keyword schemeSpecialSyntax foreign-safe-lambda
+syn keyword schemeSpecialSyntax foreign-safe-lambda*
+syn keyword schemeSpecialSyntax foreign-value
+
+syn keyword schemeSyntaxSyntax begin-for-syntax
+syn keyword schemeSyntaxSyntax define-for-syntax
+syn keyword schemeSyntaxSyntax er-macro-transformer
+syn keyword schemeSyntaxSyntax ir-macro-transformer
+syn keyword schemeSyntaxSyntax require-library-for-syntax