diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index aaca0823c4f..ecad501e664 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -295,20 +295,25 @@ NS_IMPL_ISUPPORTS(UploadLastDir::ContentPrefCallback, nsIContentPrefCallback2)
 NS_IMETHODIMP
 UploadLastDir::ContentPrefCallback::HandleCompletion(uint16_t aReason)
 {
-  nsCOMPtr<nsIFile> localFile = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
-  NS_ENSURE_STATE(localFile);
+  nsCOMPtr<nsIFile> localFile;
+  nsAutoString prefStr;
 
-  if (aReason == nsIContentPrefCallback2::COMPLETE_ERROR ||
-      !mResult) {
-    // Default to "desktop" directory for each platform
-    nsCOMPtr<nsIFile> homeDir;
-    NS_GetSpecialDirectory(NS_OS_DESKTOP_DIR, getter_AddRefs(homeDir));
-    localFile = do_QueryInterface(homeDir);
-  } else {
-    nsAutoString prefStr;
-    nsCOMPtr<nsIVariant> pref;
-    mResult->GetValue(getter_AddRefs(pref));
-    pref->GetAsAString(prefStr);
+  if (aReason == nsIContentPrefCallback2::COMPLETE_ERROR || !mResult) {
+    prefStr = Preferences::GetString("dom.input.fallbackUploadDir");
+    if (prefStr.IsEmpty()) {
+      // If no custom directory was set through the pref, default to
+      // "desktop" directory for each platform.
+      NS_GetSpecialDirectory(NS_OS_DESKTOP_DIR, getter_AddRefs(localFile));
+    }
+  }
+
+  if (!localFile) {
+    if (prefStr.IsEmpty() && mResult) {
+      nsCOMPtr<nsIVariant> pref;
+      mResult->GetValue(getter_AddRefs(pref));
+      pref->GetAsAString(prefStr);
+    }
+    localFile = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
     localFile->InitWithPath(prefStr);
   }
 
diff --git a/dom/html/test/mochitest.ini b/dom/html/test/mochitest.ini
index 340a2654481..c25fef89f41 100644
--- a/dom/html/test/mochitest.ini
+++ b/dom/html/test/mochitest.ini
@@ -600,3 +600,5 @@ skip-if = buildapp == 'b2g' # bug 1129014
 [test_image_clone_load.html]
 [test_bug1203668.html]
 [test_bug1166138.html]
+[test_filepicker_default_directory.html]
+skip-if = buildapp == 'mulet' || buildapp == 'b2g' || toolkit == 'android'
diff --git a/dom/html/test/test_filepicker_default_directory.html b/dom/html/test/test_filepicker_default_directory.html
new file mode 100644
index 00000000000..c2212baa04b
--- /dev/null
+++ b/dom/html/test/test_filepicker_default_directory.html
@@ -0,0 +1,83 @@
+<!DOCTYPE html>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1194893
+-->
+<head>
+  <title>Test for filepicker default directory</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="application/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1194893">Mozilla Bug 1194893</a>
+<div id="content">
+  <input type="file" id="f">
+</div>
+<pre id="text">
+<script class="testbody" type="application/javascript">
+
+SimpleTest.waitForExplicitFinish();
+const { Cc: Cc, Ci: Ci } = SpecialPowers;
+
+// Platform-independent directory names are #define'd in xpcom/io/nsDirectoryServiceDefs.h
+var defaultUploadDirectory = Cc["@mozilla.org/file/directory_service;1"]
+                            .getService(Ci.nsIDirectoryService)
+                            .QueryInterface(Ci.nsIProperties)
+                            .get("Desk", Ci.nsIFile);
+
+// When we want to test an upload directory other than the default, we need to
+// get a valid directory in a platform-independent way. Since NS_OS_DESKTOP_DIR
+// may fallback to NS_OS_HOME_DIR, let's use NS_OS_TMP_DIR.
+var customUploadDirectory = Cc["@mozilla.org/file/directory_service;1"]
+                            .getService(Ci.nsIDirectoryService)
+                            .QueryInterface(Ci.nsIProperties)
+                            .get("TmpD", Ci.nsIFile);
+
+// Useful for debugging
+//info("defaultUploadDirectory" + defaultUploadDirectory.path);
+//info("customUploadDirectory" + customUploadDirectory.path);
+
+var MockFilePicker = SpecialPowers.MockFilePicker;
+MockFilePicker.init(window);
+
+// need to show the MockFilePicker so .displayDirectory gets set
+var f = document.getElementById("f");
+f.focus();
+
+var testIndex = 0;
+var tests = [
+  ["", defaultUploadDirectory.path],
+  [customUploadDirectory.path, customUploadDirectory.path]
+]
+
+MockFilePicker.showCallback = function(filepicker) {
+  info(SpecialPowers.wrap(MockFilePicker).displayDirectory.path);
+
+  is(SpecialPowers.wrap(MockFilePicker).displayDirectory.path,
+  tests[testIndex][1]);
+
+  if (++testIndex == tests.length) {
+    MockFilePicker.cleanup();
+    SimpleTest.finish();
+  } else {
+    launchNextTest();
+  }
+}
+
+function launchNextTest() {
+  SpecialPowers.pushPrefEnv(
+    { 'set': [
+      ['dom.input.fallbackUploadDir', tests[testIndex][0]],
+    ]},
+  function () {
+    f.click();
+  });
+}
+
+launchNextTest();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index c7803e14045..291084294bd 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5131,3 +5131,6 @@ pref("dom.mozKillSwitch.enabled", false);
 pref("toolkit.pageThumbs.screenSizeDivisor", 7);
 pref("toolkit.pageThumbs.minWidth", 0);
 pref("toolkit.pageThumbs.minHeight", 0);
+
+// Allow customization of the fallback directory for file uploads
+pref("dom.input.fallbackUploadDir", "");
