diff --git a/lib/url-join.js b/lib/url-join.js
index f6140a4..83b1a26 100644
--- a/lib/url-join.js
+++ b/lib/url-join.js
@@ -22,7 +22,8 @@ function normalize (strArray) {
   // There must be two or three slashes in the file protocol, two slashes in anything else.
   if (strArray[0].match(/^file:\/\/\//)) {
     strArray[0] = strArray[0].replace(/^([^/:]+):\/*/, '$1:///');
-  } else {
+  } else if (!strArray[0].match(/^\[.*:.*\]/)) {
+    // If the first part is not an IPv6 host, we replace the protocol.
     strArray[0] = strArray[0].replace(/^([^/:]+):\/*/, '$1://');
   }
 
diff --git a/test/tests.js b/test/tests.js
index 2a9526e..8f91011 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -300,3 +300,24 @@ test('joins leading empty string', () => {
     '/test'
   );
 });
+
+test('joins a leading IPv6 hostname', () => {
+  assert.equal(
+    urlJoin('[2601:195:c381:3560::f42a]/', '/test'),
+    '[2601:195:c381:3560::f42a]/test'
+  );
+});
+
+test('joins a leading IPv6 host with an IPv4 address in the least significant 32 bits', () => {
+  assert.equal(
+    urlJoin('[2601:195:c381:3560::0.0.244.42]', '/test'),
+    '[2601:195:c381:3560::0.0.244.42]/test'
+  );
+});
+
+test('joins a protocol followed by an IPv6 host', () => {
+  assert.equal(
+    urlJoin('https://', '[2601:195:c381:3560::f42a]/', '/test'),
+    'https://[2601:195:c381:3560::f42a]/test'
+  );
+});