diff --git a/README.md b/README.md
index be6ce2b..e215e22 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,7 @@ If you need full functionality of any plugin, please use it directly with your p
 - [jasmine](https://github.com/glanotte/vim-jasmine) (syntax)
 - [javascript](https://github.com/pangloss/vim-javascript) (syntax, indent, compiler, ftplugin, extras)
 - [jenkins](https://github.com/martinda/Jenkinsfile-vim-syntax) (syntax, indent)
+- [json5](https://github.com/GutenYe/json5.vim) (syntax)
 - [json](https://github.com/elzr/vim-json) (syntax, indent, ftplugin)
 - [jst](https://github.com/briancollins/vim-jst) (syntax, indent)
 - [jsx](https://github.com/mxw/vim-jsx) (after)
diff --git a/build b/build
index b7c449c..cd00ddc 100755
--- a/build
+++ b/build
@@ -152,6 +152,7 @@ PACKS="
   javascript:pangloss/vim-javascript:_JAVASCRIPT
   jenkins:martinda/Jenkinsfile-vim-syntax
   json:elzr/vim-json
+  json5:GutenYe/json5.vim
   jst:briancollins/vim-jst
   jsx:mxw/vim-jsx:_ALL
   julia:JuliaEditorSupport/julia-vim
diff --git a/ftdetect/polyglot.vim b/ftdetect/polyglot.vim
index ed5f39c..4ae4ec4 100644
--- a/ftdetect/polyglot.vim
+++ b/ftdetect/polyglot.vim
@@ -447,6 +447,11 @@ autocmd BufNewFile,BufRead *.geojson setlocal filetype=json
 autocmd BufNewFile,BufRead *.template setlocal filetype=json
 augroup END
 
+augroup filetypedetect
+" json5:GutenYe/json5.vim
+au BufNewFile,BufRead *.json5 setfiletype json5
+augroup END
+
 augroup filetypedetect
 " jst:briancollins/vim-jst
 au BufNewFile,BufRead *.ejs set filetype=jst
diff --git a/syntax/json5.vim b/syntax/json5.vim
new file mode 100644
index 0000000..15943f7
--- /dev/null
+++ b/syntax/json5.vim
@@ -0,0 +1,56 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'json5') == -1
+  
+" Syntax setup {{{1
+if exists('b:current_syntax') && b:current_syntax == 'json5'
+  finish
+endif
+
+" Syntax: Strings {{{1
+syn region  json5String    start=+"+  skip=+\\\\\|\\"+  end=+"+  contains=json5Escape
+syn region  json5String    start=+'+  skip=+\\\\\|\\'+  end=+'+  contains=json5Escape
+
+" Syntax: Escape sequences
+syn match   json5Escape    "\\["\\/bfnrt]" contained
+syn match   json5Escape    "\\u\x\{4}" contained
+
+" Syntax: Numbers {{{1
+syn match   json5Number    "-\=\<\%(0\|[1-9]\d*\)\%(\.\d\+\)\=\%([eE][-+]\=\d\+\)\=\>"
+syn keyword json5Number    Infinity -Infinity
+
+" Syntax: An integer part of 0 followed by other digits is not allowed.
+syn match   json5NumError  "-\=\<0\d\.\d*\>"
+
+" Syntax: Boolean {{{1
+syn keyword json5Boolean   true false
+
+" Syntax: Null {{{1
+syn keyword json5Null      null
+
+" Syntax: Braces {{{1
+syn match   json5Braces	   "[{}\[\]]"
+syn match   json5ObjAssign /@\?\%(\I\|\$\)\%(\i\|\$\)*\s*\ze::\@!/
+
+" Syntax: Comment {{{1
+syn region  json5LineComment    start=+\/\/+ end=+$+ keepend
+syn region  json5LineComment    start=+^\s*\/\/+ skip=+\n\s*\/\/+ end=+$+ keepend fold
+syn region  json5Comment        start="/\*"  end="\*/" fold
+
+" Define the default highlighting. {{{1
+hi def link json5String             String
+hi def link json5ObjAssign          Identifier
+hi def link json5Escape             Special
+hi def link json5Number             Number
+hi def link json5Braces             Operator
+hi def link json5Null               Function
+hi def link json5Boolean            Boolean
+hi def link json5LineComment        Comment
+hi def link json5Comment            Comment
+hi def link json5NumError           Error
+
+if !exists('b:current_syntax')
+  let b:current_syntax = 'json5'
+endif
+
+" vim: fdm=marker
+
+endif