diff --git a/src/Composer/Downloader/GitDownloader.php b/src/Composer/Downloader/GitDownloader.php
index 3c6342849..7cdb40373 100644
--- a/src/Composer/Downloader/GitDownloader.php
+++ b/src/Composer/Downloader/GitDownloader.php
@@ -235,17 +235,22 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
             return;
         }
 
+        $candidateBranches = $matches[1];
         // use the first match as branch name for now
-        $branch = $matches[1][0];
+        $branch = $candidateBranches[0];
         $unpushedChanges = null;
 
         // do two passes, as if we find anything we want to fetch and then re-try
         for ($i = 0; $i <= 1; $i++) {
-            // try to find the a matching branch name in the composer remote
-            foreach ($matches[1] as $candidate) {
-                if (preg_match('{^[a-f0-9]+ refs/remotes/((?:composer|origin)/'.preg_quote($candidate).')$}mi', $refs, $match)) {
-                    $branch = $candidate;
-                    $remoteBranch = $match[1];
+            $remoteBranches = array();
+
+            // try to find matching branch names in remote repos
+            foreach ($candidateBranches as $candidate) {
+                if (preg_match_all('{^[a-f0-9]+ refs/remotes/((?:[^/]+)/'.preg_quote($candidate).')$}mi', $refs, $matches)) {
+                    foreach ($matches[1] as $match) {
+                        $branch = $candidate;
+                        $remoteBranches[] = $match;
+                    }
                     break;
                 }
             }
@@ -253,21 +258,34 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
             // if it doesn't exist, then we assume it is an unpushed branch
             // this is bad as we have no reference point to do a diff so we just bail listing
             // the branch as being unpushed
-            if (!isset($remoteBranch)) {
+            if (!$remoteBranches) {
                 $unpushedChanges = 'Branch ' . $branch . ' could not be found on the origin remote and appears to be unpushed';
             } else {
-                $command = sprintf('git diff --name-status %s...%s --', $remoteBranch, $branch);
-                if (0 !== $this->process->execute($command, $output, $path)) {
-                    throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
-                }
+                foreach ($remoteBranches as $remoteBranch) {
+                    $command = sprintf('git diff --name-status %s...%s --', $remoteBranch, $branch);
+                    if (0 !== $this->process->execute($command, $output, $path)) {
+                        throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
+                    }
 
-                $unpushedChanges = trim($output) ?: null;
+                    $output = trim($output);
+                    // keep the shortest diff from all remote branches we compare against
+                    if ($unpushedChanges === null || strlen($output) < strlen($unpushedChanges)) {
+                        $unpushedChanges = $output ?: null;
+                    }
+                }
             }
 
-            // first pass and we found unpushed changes, fetch from both remotes to make sure we have up to date
+            // first pass and we found unpushed changes, fetch from all remotes to make sure we have up to date
             // remotes and then try again as outdated remotes can sometimes cause false-positives
             if ($unpushedChanges && $i === 0) {
-                $this->process->execute('git fetch composer && git fetch origin', $output, $path);
+                $this->process->execute('git fetch --all', $output, $path);
+
+                // update list of refs after fetching
+                $command = 'git show-ref --head -d';
+                if (0 !== $this->process->execute($command, $output, $path)) {
+                    throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
+                }
+                $refs = trim($output);
             }
 
             // abort after first pass if we didn't find anything