diff --git a/package.json b/package.json
index 277ac99..40fd029 100644
--- a/package.json
+++ b/package.json
@@ -33,7 +33,7 @@
     "safe-buffer": "^5.2.1"
   },
   "devDependencies": {
-    "chai": "^4.4.1",
+    "chai": "^5.0.3",
     "eslint": "^8.56.0",
     "eslint-config-standard": "^17.1.0",
     "eslint-plugin-import": "^2.29.1",
diff --git a/test/mo-compiler-test.js b/test/mo-compiler-test.js
index 014e3e4..4796425 100644
--- a/test/mo-compiler-test.js
+++ b/test/mo-compiler-test.js
@@ -1,4 +1,4 @@
-import chai from 'chai';
+import * as chai from 'chai';
 import { promisify } from 'util';
 import path from 'path';
 import { mo } from '../index.js';
diff --git a/test/mo-parser-test.js b/test/mo-parser-test.js
index aa2ad48..723368a 100644
--- a/test/mo-parser-test.js
+++ b/test/mo-parser-test.js
@@ -1,4 +1,4 @@
-import chai from 'chai';
+import * as chai from 'chai';
 import { promisify } from 'util';
 import path from 'path';
 import { mo } from '../index.js';
diff --git a/test/po-compiler-test.js b/test/po-compiler-test.js
index 3b62d7e..18ad149 100644
--- a/test/po-compiler-test.js
+++ b/test/po-compiler-test.js
@@ -2,7 +2,7 @@ import { EOL } from 'os';
 import { promisify } from 'util';
 import path from 'path';
 import { readFile as fsReadFile } from 'fs';
-import chai from 'chai';
+import * as chai from 'chai';
 import { po } from '../index.js';
 import { fileURLToPath } from 'url';
 
diff --git a/test/po-obsolete-test.js b/test/po-obsolete-test.js
index 61b6bf2..f0e696f 100644
--- a/test/po-obsolete-test.js
+++ b/test/po-obsolete-test.js
@@ -1,5 +1,5 @@
 import { EOL } from 'os';
-import chai from 'chai';
+import * as chai from 'chai';
 import { promisify } from 'util';
 import path from 'path';
 import fs from 'fs';
diff --git a/test/po-parser-test.js b/test/po-parser-test.js
index 4bdd7c8..3a006c1 100644
--- a/test/po-parser-test.js
+++ b/test/po-parser-test.js
@@ -1,4 +1,4 @@
-import chai from 'chai';
+import * as chai from 'chai';
 import { promisify } from 'util';
 import path from 'path';
 import fs from 'fs';
diff --git a/test/shared.js b/test/shared.js
index 3712006..c40dfd6 100644
--- a/test/shared.js
+++ b/test/shared.js
@@ -1,6 +1,6 @@
 'use strict';
 
-import chai from 'chai';
+import * as chai from 'chai';
 import { promisify } from 'util';
 import path from 'path';
 import { formatCharset, parseHeader, generateHeader, foldLine, parseNPluralFromHeadersSafely } from '../lib/shared.js';