diff --git a/lib/body.js b/lib/body.js
index fb7ffc3..ea6e6fb 100644
--- a/lib/body.js
+++ b/lib/body.js
@@ -132,7 +132,7 @@ class Body {
 
     // do not keep the process open just for this timeout, even
     // though we expect it'll get cleared eventually.
-    if (resTimeout) {
+    if (resTimeout && resTimeout.unref) {
       resTimeout.unref()
     }
 
diff --git a/test/body.js b/test/body.js
index 291c4e2..6c6c71c 100644
--- a/test/body.js
+++ b/test/body.js
@@ -231,6 +231,20 @@ t.test('json', async t => {
   })
 })
 
+t.test('handles environments where setTimeout does not have unref', async t => {
+  const originalSetTimeout = setTimeout
+  // simulate environments without unref()
+  global.setTimeout = (func, time) =>
+    Object.assign(originalSetTimeout(func, time), { unref: null })
+  t.teardown(() => global.setTimeout = originalSetTimeout)
+
+  t.doesNotThrow(async () => {
+    const b = new Body(new Blob('a=1'), { timeout: 100 })
+    await b.text()
+    t.end()
+  })
+})
+
 t.test('write to streams', async t => {
   const w = body => Body.writeToStream(
     new Minipass({ encoding: 'utf8' }),