diff --git a/crates/ide-language/src/registry.rs b/crates/ide-language/src/registry.rs
index a1ee0ae0e..3f68042fd 100644
--- a/crates/ide-language/src/registry.rs
+++ b/crates/ide-language/src/registry.rs
@@ -40,6 +40,7 @@ const BUILTIN: &[(&str, &str)] = &[
     ("groovy", include_str!("../../../languages/groovy.toml")),
     ("haskell", include_str!("../../../languages/haskell.toml")),
     ("hcl", include_str!("../../../languages/hcl.toml")),
+    ("helm-template", include_str!("../../../languages/helm-template.toml")),
     ("html", include_str!("../../../languages/html.toml")),
     ("http", include_str!("../../../languages/http.toml")),
     ("ignore", include_str!("../../../languages/ignore.toml")),
@@ -548,6 +549,7 @@ mod tests {
         "Groovy",
         "Haskell",
         "Haxe",
+        "Helm Template",
         "HXML",
         "HTTP",
         "IDL",
@@ -841,6 +843,30 @@ mod tests {
         assert!(reg.is_framework_marker(&root.join("src/manage.py")));
     }
 
+    #[test]
+    fn helm_charts_make_yaml_and_notes_in_templates_folders_helm_templates() {
+        let reg = reg();
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        let detect = |file: &str| reg.detect(&root.join(file), None).as_str().to_owned();
+        std::fs::create_dir_all(root.join("charts/podinfo/templates/tests")).unwrap();
+        std::fs::create_dir_all(root.join("k8s/templates")).unwrap();
+        std::fs::write(root.join("charts/podinfo/Chart.yaml"), "apiVersion: v2\nname: podinfo\n").unwrap();
+        assert_eq!(detect("charts/podinfo/Chart.yaml"), "yaml");
+        assert_eq!(detect("charts/podinfo/values.yaml"), "yaml");
+        assert_eq!(detect("charts/podinfo/templates/deployment.yaml"), "helm-template");
+        assert_eq!(detect("charts/podinfo/templates/tests/connection.yml"), "helm-template");
+        assert_eq!(detect("charts/podinfo/templates/_helpers.tpl"), "helm-template");
+        assert_eq!(detect("charts/podinfo/templates/NOTES.txt"), "helm-template");
+        // No `Chart.yaml` / `Chart.yml` above this `templates` folder.
+        assert_eq!(detect("k8s/templates/deployment.yaml"), "yaml");
+        assert_eq!(detect("common.gotmpl"), "helm-template");
+        // Outside a chart, `.tpl` belongs to other template engines (Smarty, Terraform).
+        assert_ne!(detect("site/index.tpl"), "helm-template");
+        assert!(reg.is_framework_marker(&root.join("charts/podinfo/Chart.yaml")));
+        assert!(reg.is_framework_marker(&root.join("charts/podinfo/Chart.yml")));
+    }
+
     #[test]
     fn the_django_fixture_has_templates_and_a_page() {
         let reg = reg();
diff --git a/languages/helm-template.toml b/languages/helm-template.toml
new file mode 100644
index 000000000..c4a6a3846
--- /dev/null
+++ b/languages/helm-template.toml
@@ -0,0 +1,16 @@
+id = "helm-template"
+name = "Helm Template"
+# `.tpl` is Smarty, Terraform and other template engines too: only charts claim it (below).
+extensions = ["gotmpl"]
+line-comment = "#"
+block-comment = ["{{/*", "*/}}"]
+indent = { tab-size = 2, insert-spaces = true }
+ui-mode = "Helm Template"
+
+# Helm charts: YAML, template and notes files in a `templates` folder.
+# No YAML formatter or strict YAML language server: Go `{{ … }}` actions are
+# not valid YAML until rendered by `helm template`.
+[[framework-files]]
+folder = "templates"
+extensions = ["yaml", "yml", "tpl", "txt"]
+root-markers = ["Chart.yaml", "Chart.yml"]
diff --git a/src/editor/core/cm/helm.test.ts b/src/editor/core/cm/helm.test.ts
new file mode 100644
index 000000000..f4b6a0394
--- /dev/null
+++ b/src/editor/core/cm/helm.test.ts
@@ -0,0 +1,54 @@
+import { describe, expect, it } from "vitest";
+import { EditorState } from "@codemirror/state";
+import { completedSyntaxTree } from "@/test/syntax";
+import { classHighlighter, highlightTree } from "@lezer/highlight";
+import { findLanguageDescription, loadSupport } from "./languages";
+
+async function tokens(source: string) {
+  const desc = findLanguageDescription("Helm Template", "templates/applications.yaml")!;
+  const support = await loadSupport(desc);
+  const state = EditorState.create({ doc: source, extensions: [support!] });
+  const result: { text: string; style: string }[] = [];
+  highlightTree(completedSyntaxTree(state), classHighlighter, (from, to, style) =>
+    result.push({ text: source.slice(from, to), style }),
+  );
+  return result;
+}
+
+describe("Helm Template mode", () => {
+  it("highlights YAML outside and Go template actions inside {{ … }}", async () => {
+    const src = [
+      "{{- range .Values.applications }}",
+      "{{- $config := $.Values.config -}}",
+      "apiVersion: argoproj.io/v1alpha1",
+      "metadata:",
+      '  name: {{ printf "example.%s" .name | quote }}',
+      '  image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"',
+      "{{/* block note */}}",
+      "{{- end }}",
+    ].join("\n");
+    const out = await tokens(src);
+    expect(out).toContainEqual(expect.objectContaining({ text: "range", style: "tok-keyword" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: "$config", style: "tok-variableName" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: ".Values.applications", style: "tok-propertyName" }));
+    expect(out).toContainEqual(
+      expect.objectContaining({ text: ".Values.image.repository", style: "tok-propertyName" }),
+    );
+    expect(out).toContainEqual(expect.objectContaining({ text: "apiVersion", style: "tok-propertyName" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: "{{/* block note */}}", style: "tok-comment" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: "end", style: "tok-keyword" }));
+  });
+
+  it("reads comments with trim markers", async () => {
+    const out = await tokens("{{- /* trimmed note */ -}}\nkind: Deployment");
+    expect(out).toContainEqual(expect.objectContaining({ text: "{{- /* trimmed note */ -}}", style: "tok-comment" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: "kind", style: "tok-propertyName" }));
+  });
+
+  it("keeps multi-line {{/* … */}} comments across lines", async () => {
+    const out = await tokens("{{/* line 1\nline 2 */}}\nreplicas: 3");
+    expect(out).toContainEqual(expect.objectContaining({ text: "{{/* line 1", style: "tok-comment" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: "line 2 */}}", style: "tok-comment" }));
+    expect(out).toContainEqual(expect.objectContaining({ text: "replicas", style: "tok-propertyName" }));
+  });
+});
diff --git a/src/editor/core/cm/helm.ts b/src/editor/core/cm/helm.ts
new file mode 100644
index 000000000..67ed36501
--- /dev/null
+++ b/src/editor/core/cm/helm.ts
@@ -0,0 +1,296 @@
+// Helm Template editor mode: YAML outside `{{ … }}`, Go `text/template` + Sprig/Helm
+// actions and `{{/* … */}}` comments inside. Each region runs on a sub-stream bounded
+// at the next delimiter so `{{ … }}` never breaks YAML key/value tokenization.
+import { LanguageSupport, StreamLanguage, StringStream, type StreamParser } from "@codemirror/language";
+import { tags } from "@lezer/highlight";
+
+type HelmState<Y> = {
+  yaml: Y;
+  inAction: boolean;
+  inComment: boolean;
+  inRawString: boolean;
+  quote: '"' | "'" | null;
+  indentUnit: number;
+};
+
+const OPEN = /\{\{-?/;
+const CLOSE = /-?\}\}/;
+// `{{/* … */}}`, or with trim markers `{{- /* … */ -}}` (Go requires the space there).
+const COMMENT_OPEN = /^\s*\/\*/;
+const COMMENT_CLOSE = /\*\/\s*-?\}\}/;
+
+const KEYWORDS = new Set(["if", "else", "end", "range", "with", "define", "template", "block", "break", "continue"]);
+const ATOMS = new Set(["true", "false", "nil"]);
+const FUNCTIONS = new Set([
+  "and",
+  "b64dec",
+  "b64enc",
+  "call",
+  "coalesce",
+  "contains",
+  "default",
+  "dict",
+  "empty",
+  "eq",
+  "fail",
+  "first",
+  "fromJson",
+  "fromYaml",
+  "ge",
+  "get",
+  "gt",
+  "has",
+  "hasKey",
+  "hasPrefix",
+  "hasSuffix",
+  "html",
+  "include",
+  "indent",
+  "index",
+  "int",
+  "int64",
+  "join",
+  "js",
+  "keys",
+  "kindIs",
+  "kindOf",
+  "last",
+  "le",
+  "len",
+  "list",
+  "lookup",
+  "lower",
+  "lt",
+  "merge",
+  "mustMerge",
+  "ne",
+  "nindent",
+  "not",
+  "or",
+  "pluck",
+  "print",
+  "printf",
+  "println",
+  "quote",
+  "regexMatch",
+  "replace",
+  "required",
+  "semverCompare",
+  "set",
+  "sha256sum",
+  "slice",
+  "snakecase",
+  "squote",
+  "ternary",
+  "title",
+  "toJson",
+  "toPrettyJson",
+  "toString",
+  "toStrings",
+  "toToml",
+  "toYaml",
+  "tpl",
+  "trim",
+  "trimAll",
+  "trimPrefix",
+  "trimSuffix",
+  "trunc",
+  "typeIs",
+  "typeOf",
+  "unset",
+  "upper",
+  "urlquery",
+  "values",
+]);
+
+function tokenAction<Y>(stream: StringStream, state: HelmState<Y>): string | null {
+  if (state.inRawString) {
+    const end = stream.string.indexOf("`", stream.pos);
+    if (end < 0) {
+      stream.skipToEnd();
+      return "string";
+    }
+    stream.pos = end + 1;
+    state.inRawString = false;
+    return "string";
+  }
+
+  if (stream.eatSpace()) return null;
+
+  const rest = stream.string.slice(stream.pos);
+  const close = CLOSE.exec(rest);
+  if (close?.index === 0) {
+    stream.pos += close[0].length;
+    state.inAction = false;
+    return "helmDelimiter";
+  }
+
+  const ch = stream.peek();
+  if (ch === "`") {
+    stream.next();
+    state.inRawString = true;
+    return tokenAction(stream, state);
+  }
+  if (ch === '"') {
+    stream.match(/^"(?:[^"\\]|\\.)*"?/);
+    return "string";
+  }
+  if (ch === "'") {
+    stream.match(/^'(?:[^'\\]|\\.)*'?/);
+    return "string";
+  }
+  if (stream.match(/^:=/)) return "operator";
+  if (ch === "|" || ch === "=" || ch === "(" || ch === ")") {
+    stream.next();
+    return ch === "|" ? "operator" : "punctuation";
+  }
+  if (ch === "$") {
+    stream.match(/^\$[A-Za-z0-9_]*/);
+    return "variableName";
+  }
+  if (ch === ".") {
+    if (stream.match(/^\.[A-Za-z_][A-Za-z0-9_]*/)) return "propertyName";
+    stream.next();
+    return "operator";
+  }
+  if (stream.match(/^-?(?:0x[0-9a-fA-F]+|\d+(?:\.\d+)?)/)) return "number";
+  if (stream.match(/^[A-Za-z_][A-Za-z0-9_]*/)) {
+    const word = stream.current();
+    if (KEYWORDS.has(word)) return "keyword";
+    if (ATOMS.has(word)) return "bool";
+    if (FUNCTIONS.has(word)) return "helmFunc";
+    return "variableName";
+  }
+
+  stream.next();
+  return null;
+}
+
+export function helmParser<Y>(yaml: StreamParser<Y>): StreamParser<HelmState<Y>> {
+  const copy = (base: StreamParser<Y>, state: Y): Y =>
+    base.copyState
+      ? base.copyState(state)
+      : (Object.fromEntries(
+          Object.entries(state as object).map(([k, v]) => [k, Array.isArray(v) ? v.slice() : v]),
+        ) as Y);
+
+  const withinYaml = (stream: StringStream, end: number, state: HelmState<Y>): string | null => {
+    if (state.quote) {
+      const q = state.quote;
+      while (stream.pos < end) {
+        const ch = stream.string[stream.pos];
+        if (ch === "\\" && q === '"' && stream.pos + 1 < end) {
+          stream.pos += 2;
+          continue;
+        }
+        stream.pos++;
+        if (ch === q) {
+          state.quote = null;
+          break;
+        }
+      }
+      return "string";
+    }
+    const ch = stream.string[stream.pos];
+    if (ch === '"' || ch === "'") {
+      // Quoted scalar containing `{{ … }}` later on the same line: consume up to `end` or closing quote.
+      if (end < stream.string.length) {
+        stream.pos++;
+        state.quote = ch;
+        while (stream.pos < end) {
+          const c = stream.string[stream.pos];
+          if (c === "\\" && ch === '"' && stream.pos + 1 < end) {
+            stream.pos += 2;
+            continue;
+          }
+          stream.pos++;
+          if (c === ch) {
+            state.quote = null;
+            break;
+          }
+        }
+        return "string";
+      }
+    }
+    const sub = new StringStream(stream.string.slice(0, end), 2, stream.indentUnit);
+    sub.pos = stream.pos;
+    sub.start = stream.start;
+    const style = yaml.token(sub, state.yaml);
+    stream.pos = Math.max(sub.pos, stream.pos + (sub.pos === stream.pos ? 1 : 0));
+    return style;
+  };
+
+  return {
+    name: "helm-template",
+    languageData: {
+      ...yaml.languageData,
+      commentTokens: { line: "#", block: { open: "{{/*", close: "*/}}" } },
+    },
+    tokenTable: {
+      ...yaml.tokenTable,
+      atom: tags.propertyName,
+      helmDelimiter: tags.special(tags.brace),
+      helmFunc: tags.function(tags.variableName),
+    },
+    startState: (indentUnit) => ({
+      yaml: yaml.startState!(indentUnit),
+      inAction: false,
+      inComment: false,
+      inRawString: false,
+      quote: null,
+      indentUnit,
+    }),
+    copyState: (s) => ({ ...s, yaml: copy(yaml, s.yaml) }),
+    blankLine: (s, unit) => {
+      s.quote = null;
+      yaml.blankLine?.(s.yaml, unit);
+    },
+    token(stream, state) {
+      if (stream.sol()) state.quote = null;
+
+      if (state.inComment) {
+        const rest = stream.string.slice(stream.pos);
+        const close = COMMENT_CLOSE.exec(rest);
+        if (!close) {
+          stream.skipToEnd();
+          return "comment";
+        }
+        stream.pos += close.index + close[0].length;
+        state.inComment = false;
+        return "comment";
+      }
+
+      if (state.inAction) {
+        return tokenAction(stream, state);
+      }
+
+      const rest = stream.string.slice(stream.pos);
+      const open = OPEN.exec(rest);
+      if (open?.index === 0) {
+        const comment = COMMENT_OPEN.exec(stream.string.slice(stream.pos + open[0].length));
+        if (comment) {
+          stream.pos += open[0].length + comment[0].length;
+          const close = COMMENT_CLOSE.exec(stream.string.slice(stream.pos));
+          if (!close) {
+            stream.skipToEnd();
+            state.inComment = true;
+          } else {
+            stream.pos += close.index + close[0].length;
+          }
+          return "comment";
+        }
+        stream.pos += open[0].length;
+        state.inAction = true;
+        return "helmDelimiter";
+      }
+
+      const end = open ? stream.pos + open.index : stream.string.length;
+      return withinYaml(stream, end, state);
+    },
+  };
+}
+
+export async function helmTemplate(): Promise<LanguageSupport> {
+  const { yaml } = await import("@codemirror/legacy-modes/mode/yaml");
+  return new LanguageSupport(StreamLanguage.define(helmParser(yaml)));
+}
diff --git a/src/editor/core/cm/languages.ts b/src/editor/core/cm/languages.ts
index 752a437af..bd73cd992 100644
--- a/src/editor/core/cm/languages.ts
+++ b/src/editor/core/cm/languages.ts
@@ -137,6 +137,12 @@ const OWN_MODES = [
     extensions: ["djhtml"],
     load: () => import("./django").then((m) => m.django()),
   }),
+  LanguageDescription.of({
+    name: "Helm Template",
+    alias: ["helm-template", "gotmpl"],
+    extensions: ["gotmpl"],
+    load: () => import("./helm").then((m) => m.helmTemplate()),
+  }),
   LanguageDescription.of({
     name: "Astro",
     extensions: ["astro"],
diff --git a/src/editor/lsp/syntaxErrors.ts b/src/editor/lsp/syntaxErrors.ts
index f95559266..9ff062e26 100644
--- a/src/editor/lsp/syntaxErrors.ts
+++ b/src/editor/lsp/syntaxErrors.ts
@@ -19,7 +19,7 @@ const INSPECT_DELAY = 500;
  * Dialects the grammar doesn't follow: the database support checks SQL, and Django templates
  * borrow the HTML grammar, which reads `{% if a > b %}` as broken markup.
  */
-const SKIPPED = new Set(["sql", "plaintext", "django-html"]);
+const SKIPPED = new Set(["sql", "plaintext", "django-html", "helm-template"]);
 const RUNNING: ReadonlySet<ServerStatus> = new Set<ServerStatus>(["starting", "ready", "busy"]);
 
 let checked: Promise<ReadonlySet<string>> | null = null;
diff --git a/src/test/syntax.test.ts b/src/test/syntax.test.ts
index 3d159e73a..1aea7023e 100644
--- a/src/test/syntax.test.ts
+++ b/src/test/syntax.test.ts
@@ -23,6 +23,7 @@ const cases = [
   ["JSP", "<% if (ready) { %><p><%= value %></p><% } %>"],
   ["Angular Template", "@if (ready) {\n  <p>{{ value }}</p>\n}"],
   ["Django Template", "{% if ready %}\n  <p>{{ value|lower }}</p>\n{% endif %}"],
+  ["Helm Template", "{{- range .Values.apps }}\napiVersion: v1\nmetadata:\n  name: {{ .name | quote }}\n{{- end }}"],
 ];
 
 function highlights(state: EditorState) {
diff --git a/src/ui/icons.tsx b/src/ui/icons.tsx
index e7e181477..ddfcc9957 100644
--- a/src/ui/icons.tsx
+++ b/src/ui/icons.tsx
@@ -1057,7 +1057,7 @@ const EXT_ICONS = table({
   "file-json": "json jsonc json5 jsonl ndjson geojson topojson webmanifest har avsc code-workspace code-snippets map",
   "file-md": "md mdx markdown mdown mkd mkdn mdwn ronn workbook",
   "file-rst": "rst",
-  "file-yaml": "yaml yml",
+  "file-yaml": "yaml yml gotmpl",
   "file-toml": "toml",
   "file-text": "txt text",
   "file-log": "log",