diff --git a/package.json b/package.json
index fa6fa3b7..3f9732b0 100644
--- a/package.json
+++ b/package.json
@@ -53,7 +53,7 @@
     "c12": "^3.2.0",
     "citty": "^0.1.6",
     "consola": "^3.4.2",
-    "eta": "^2.2.0",
+    "eta": "^4.0.1",
     "js-yaml": "^4.1.0",
     "lodash": "^4.17.21",
     "nanoid": "^5.1.5",
diff --git a/src/templates-worker.ts b/src/templates-worker.ts
index 2d01c750..00807c6c 100644
--- a/src/templates-worker.ts
+++ b/src/templates-worker.ts
@@ -2,7 +2,7 @@ import * as module from "node:module";
 import * as path from "node:path";
 import * as url from "node:url";
 import { consola } from "consola";
-import * as Eta from "eta";
+import { Eta } from "eta";
 import lodash from "lodash";
 import type { CodeGenProcess } from "./code-gen-process.js";
 import type { CodeGenConfig } from "./configuration.js";
@@ -10,6 +10,10 @@ import type { FileSystem } from "./util/file-system.js";
 
 const require = module.createRequire(import.meta.url);
 
+const eta = new Eta({
+  functionHeader: "const includeFile = options.includeFile;",
+});
+
 export class TemplatesWorker {
   config: CodeGenConfig;
   fileSystem: FileSystem;
@@ -214,31 +218,20 @@ export class TemplatesWorker {
 
   renderTemplate = (
     template: string,
-    configuration: object,
-    options: object = {},
+    configuration: Record<string, unknown>,
   ) => {
     if (!template) return "";
 
-    return Eta.render(
-      template,
+    return eta.render(
+      eta.compile(template, { async: false }),
       {
         ...this.getRenderTemplateData(),
         ...configuration,
       },
       {
-        async: false,
-        ...options,
-        includeFile: (
-          path: string,
-          configuration: object,
-          options: object = {},
-        ) => {
-          return this.renderTemplate(
-            this.getTemplateContent(path),
-            configuration,
-            options,
-          );
-        },
+        // @ts-expect-error eta's meta options lack includeFile despite runtime support
+        includeFile: (path: string, configuration: Record<string, string>) =>
+          this.renderTemplate(this.getTemplateContent(path), configuration),
       },
     );
   };
diff --git a/yarn.lock b/yarn.lock
index eaad7bb8..f7194ab7 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2060,10 +2060,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"eta@npm:^2.2.0":
-  version: 2.2.0
-  resolution: "eta@npm:2.2.0"
-  checksum: 10c0/643b54d9539d2761bf6c5f4f48df1a5ea2d46c7f5a5fdc47a7d4802a8aa2b6262d4d61f724452e226c18cf82db02d48e65293fcc548f26a3f9d75a5ba7c3b859
+"eta@npm:^4.0.1":
+  version: 4.0.1
+  resolution: "eta@npm:4.0.1"
+  checksum: 10c0/a7dc8641705a01373393aba6d0998f7571735c4f5444aa9c3375b2574a93ef3be80cfd5c7d1f8d6f0e56a83a14a7db451195ed3ceeab145f23492bb5b41d1ece
   languageName: node
   linkType: hard
 
@@ -3777,7 +3777,7 @@ __metadata:
     c12: "npm:^3.2.0"
     citty: "npm:^0.1.6"
     consola: "npm:^3.4.2"
-    eta: "npm:^2.2.0"
+    eta: "npm:^4.0.1"
     js-yaml: "npm:^4.1.0"
     lodash: "npm:^4.17.21"
     nanoid: "npm:^5.1.5"