diff --git a/book/src/generated/lang-support.md b/book/src/generated/lang-support.md
index fdec02702..25b22a327 100644
--- a/book/src/generated/lang-support.md
+++ b/book/src/generated/lang-support.md
@@ -95,6 +95,7 @@
 | julia | ✓ | ✓ | ✓ | `julia` |
 | just | ✓ | ✓ | ✓ |  |
 | kdl | ✓ | ✓ | ✓ |  |
+| koka | ✓ |  | ✓ |  |
 | kotlin | ✓ |  |  | `kotlin-language-server` |
 | latex | ✓ | ✓ |  | `texlab` |
 | ld | ✓ |  | ✓ |  |
diff --git a/languages.toml b/languages.toml
index f0d6771fc..85d619b89 100644
--- a/languages.toml
+++ b/languages.toml
@@ -3230,6 +3230,18 @@ indent = { tab-width = 2, unit = "  " }
 name = "hocon"
 source = { git = "https://github.com/antosha417/tree-sitter-hocon", rev = "c390f10519ae69fdb03b3e5764f5592fb6924bcc" }
 
+[[language]]
+name = "koka"
+scope = "source.koka"
+injection-regex = "koka"
+file-types = ["kk"]
+comment-token = "//"
+indent = { tab-width = 8, unit = "  " }
+
+[[grammar]]
+name = "koka"
+source = { git = "https://github.com/mtoohey31/tree-sitter-koka", rev = "2527e152d4b6a79fd50aebd8d0b4b4336c94a034" }
+
 [[language]]
 name = "tact"
 scope = "source.tact"
diff --git a/runtime/queries/koka/highlights.scm b/runtime/queries/koka/highlights.scm
new file mode 100644
index 000000000..fead98384
--- /dev/null
+++ b/runtime/queries/koka/highlights.scm
@@ -0,0 +1,272 @@
+; Function calls
+
+(appexpr
+  function: (appexpr
+    (atom
+      (qidentifier
+        [
+          (qvarid) @function
+          (qidop) @function
+          (identifier
+            [(varid) (idop)] @function)
+        ])))
+  ["(" (block) (fnexpr)])
+
+(ntlappexpr
+  function: (ntlappexpr
+    (atom
+      (qidentifier
+        [
+          (qvarid) @function
+          (qidop) @function
+          (identifier
+            [(varid) (idop)] @function)
+        ])))
+  ["(" (block) (fnexpr)])
+
+(appexpr
+  field: (atom
+    (qidentifier
+      [
+        (qvarid) @function
+        (qidop) @function
+        (identifier
+          [(varid) (idop)] @function)
+      ])))
+
+(appexpr
+  (appexpr
+    field: (atom
+      (qidentifier
+        [
+          (qvarid) @variable
+          (qidop) @variable
+          (identifier
+            [(varid) (idop)] @variable)
+        ])))
+  "[")
+
+(ntlappexpr
+  field: (atom
+    (qidentifier
+      [
+        (qvarid) @function
+        (qidop) @function
+        (identifier
+          [(varid) (idop)] @function)
+      ])))
+
+(ntlappexpr
+  (ntlappexpr
+    field: (atom
+      (qidentifier
+        [
+          (qvarid) @variable
+          (qidop) @variable
+          (identifier
+            [(varid) (idop)] @variable)
+        ])))
+  "[")
+
+[
+  "initially"
+  "finally"
+] @function.special
+
+; Function definitions
+
+(puredecl
+  (funid
+    (identifier
+      [(varid) (idop)] @function)))
+
+(fundecl
+  (funid
+    (identifier
+      [(varid) (idop)] @function)))
+
+(operation
+  (identifier
+    [(varid) (idop)] @function))
+
+; Identifiers
+
+(puredecl
+  (binder
+    (identifier
+      [(varid) (idop)] @constant)))
+
+; TODO: Highlight vars differently once helix has an appropriate highlight query
+; for that purpose.
+
+(pparameter
+  (pattern
+    (identifier
+      (varid) @variable.parameter)))
+
+(paramid
+  (identifier
+    (varid) @variable.parameter))
+
+(typedecl
+  "effect"
+  (varid) @type)
+
+(typeid
+  (varid) @type)
+
+(tbinder
+  (varid) @type)
+
+(typecon
+  (varid) @type)
+
+(qvarid
+  (qid) @namespace)
+
+(modulepath (varid) @namespace)
+
+(qconid) @namespace
+
+(qidop) @namespace
+
+(varid) @variable
+
+(conid) @constructor
+
+; Operators
+
+[
+  "!"
+  "~"
+  "="
+  ":="
+  (idop)
+  (op)
+  (qidop)
+] @operator
+
+; Keywords
+
+[
+  "as"
+  "behind"
+  (externtarget)
+  "forall"
+  "handle"
+  "handler"
+  "in"
+  "infix"
+  "infixl"
+  "infixr"
+  "inject"
+  "mask"
+  "other"
+  "pub"
+  "public"
+  "some"
+] @keyword
+
+[
+  "con"
+  "control"
+  "ctl"
+  "fn"
+  "fun"
+  "rawctl"
+  "rcontrol"
+] @keyword.function
+
+"with" @keyword.control
+
+[
+  "elif"
+  "else"
+  "if"
+  "match"
+  "then"
+] @keyword.control.conditional
+
+[
+  "import"
+  "include"
+  "module"
+] @keyword.control.import
+
+[
+  "alias"
+  "effect"
+  "struct"
+  "type"
+  "val"
+  "var"
+] @keyword.storage.type
+
+[
+  "abstract"
+  "co"
+  "extend"
+  "extern"
+  "fbip"
+  "final"
+  "fip"
+  "inline"
+  "linear"
+  "named"
+  "noinline"
+  "open"
+  "override"
+  "raw"
+  "rec"
+  "ref"
+  "reference"
+  "scoped"
+  "tail"
+  "value"
+] @keyword.storage.modifier
+
+"return" @keyword.control.return
+
+; Delimiters
+
+(matchrule "|" @punctuation.delimiter)
+
+[
+  ","
+  "->"
+  "."
+  ":"
+  "::"
+  "<-"
+  ";"
+] @punctuation.delimiter
+
+[
+  "<"
+  ">"
+  "("
+  ")"
+  "["
+  "]"
+  "{"
+  "}"
+] @punctuation.bracket
+
+; Literals
+
+[
+  (string)
+  (char)
+] @string
+
+(escape) @constant.character.escape
+
+(float) @constant.numeric.float
+(int) @constant.numeric.integer
+
+; Comment
+
+[
+  (linecomment)
+  (blockcomment)
+] @comment
diff --git a/runtime/queries/koka/indents.scm b/runtime/queries/koka/indents.scm
new file mode 100644
index 000000000..0a47bcbbd
--- /dev/null
+++ b/runtime/queries/koka/indents.scm
@@ -0,0 +1,39 @@
+[
+  (appexpr ["[" "("]) ; Applications.
+  (ntlappexpr ["[" "("])
+  (atom ["[" "("]) ; Lists and tuples.
+  (program (moduledecl "{")) ; Braced module declarations.
+  (funbody)
+  (block)
+  (handlerexpr)
+  (opclausex)
+] @indent
+
+[
+  (typedecl
+    [(typeid) (opdecls)]) ; Avoid matching single-operation effects.
+  (externdecl)
+  (matchexpr)
+  (matchrule)
+
+  ; For ifexprs, branches (once they exist) will contain blocks if they're
+  ; indented so we just need to make sure the initial indent happens when we're
+  ; creating them.
+  "then"
+  "else"
+] @indent @extend
+
+(matchrule "->" @indent @extend)
+
+; Handling for error recovery.
+(ERROR "fun") @indent @extend
+(ERROR "match") @indent @extend
+(ERROR "->" @indent.always @extend)
+
+; Don't outdent on function parameter declarations.
+(atom ")" @outdent @extend.prevent-once)
+
+[
+  "]"
+  "}"
+] @outdent @extend.prevent-once
diff --git a/runtime/queries/koka/injections.scm b/runtime/queries/koka/injections.scm
new file mode 100644
index 000000000..1d5b8e331
--- /dev/null
+++ b/runtime/queries/koka/injections.scm
@@ -0,0 +1,2 @@
+([(linecomment) (blockcomment)] @injection.content
+ (#set! injection.language "comment"))
diff --git a/runtime/queries/koka/locals.scm b/runtime/queries/koka/locals.scm
new file mode 100644
index 000000000..f8a83e0cb
--- /dev/null
+++ b/runtime/queries/koka/locals.scm
@@ -0,0 +1,30 @@
+(modulebody) @local.scope
+
+(block) @local.scope
+
+(pattern
+  (identifier
+    (varid) @local.definition))
+
+(decl
+  (apattern
+    (pattern
+      (identifier
+        (varid) @local.definition))))
+
+(puredecl
+  (funid
+    (identifier
+      (varid) @local.definition)))
+
+(puredecl
+  (binder
+    (identifier
+      (varid) @local.definition)))
+
+(decl
+  (binder
+    (identifier
+      (varid) @local.definition)))
+
+(identifier (varid) @local.reference)