diff --git a/src/parser/PhutilURI.php b/src/parser/PhutilURI.php
--- a/src/parser/PhutilURI.php
+++ b/src/parser/PhutilURI.php
@@ -350,6 +350,13 @@
       return false;
     }
 
+    // If the second part only contains digits, assume we're looking at
+    // casually specified "domain.com:123" URI, not a Git URI pointed at an
+    // entirely numeric relative path.
+    if (preg_match('(^\d+\z)', $last)) {
+      return false;
+    }
+
     // If the first part has a "." or an "@" in it, interpret it as a domain
     // or a "user@host" string.
     if (preg_match('([.@])', $head)) {
diff --git a/src/parser/__tests__/PhutilURITestCase.php b/src/parser/__tests__/PhutilURITestCase.php
--- a/src/parser/__tests__/PhutilURITestCase.php
+++ b/src/parser/__tests__/PhutilURITestCase.php
@@ -177,6 +177,14 @@
 
     $uri = new PhutilURI('user@localhost:todo.txt');
     $this->assertEqual('localhost', $uri->getDomain());
+
+    // This could either be a Git URI with relative path "22", or a normal URI
+    // with port "22". We should assume it is a port number because this is
+    // relatively common, while relative Git URIs pointing at numeric filenames
+    // are bizarre.
+    $uri = new PhutilURI('domain.com:22');
+    $this->assertEqual('domain.com', $uri->getDomain());
+    $this->assertEqual('22', $uri->getPort());
   }
 
   public function testDefaultPorts() {