diff --git a/devtools/client/netmonitor/src/components/request-list-header.js b/devtools/client/netmonitor/src/components/request-list-header.js
index 5e93a44873d9..22a8b8e44d99 100644
--- a/devtools/client/netmonitor/src/components/request-list-header.js
+++ b/devtools/client/netmonitor/src/components/request-list-header.js
@@ -115,7 +115,7 @@ const RequestListHeader = createClass({
                 id: `requests-list-${name}-button`,
                 className: `requests-list-header-button`,
                 "data-sorted": sorted,
-                title: sortedTitle,
+                title: sortedTitle ? `${label} (${sortedTitle})` : label,
                 onClick: () => sortBy(name),
               },
                 name === "waterfall"
diff --git a/devtools/client/netmonitor/test/browser.ini b/devtools/client/netmonitor/test/browser.ini
index e03ba632afb2..25a8be7964ef 100644
--- a/devtools/client/netmonitor/test/browser.ini
+++ b/devtools/client/netmonitor/test/browser.ini
@@ -72,6 +72,7 @@ support-files =
 [browser_net_charts-06.js]
 [browser_net_charts-07.js]
 [browser_net_clear.js]
+[browser_net_column_headers_tooltips.js]
 [browser_net_columns_last_column.js]
 [browser_net_columns_pref.js]
 [browser_net_columns_reset.js]
diff --git a/devtools/client/netmonitor/test/browser_net_column_headers_tooltips.js b/devtools/client/netmonitor/test/browser_net_column_headers_tooltips.js
new file mode 100644
index 000000000000..e12e0373c7e3
--- /dev/null
+++ b/devtools/client/netmonitor/test/browser_net_column_headers_tooltips.js
@@ -0,0 +1,25 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Bug 1377094 - Test that all column headers have tooltips.
+ */
+
+add_task(function* () {
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
+  info("Starting test... ");
+
+  let { document } = monitor.panelWin;
+
+  let headers = document.querySelectorAll(".requests-list-header-button");
+  for (let header of headers) {
+    const buttonText = header.querySelector(".button-text").textContent;
+    const tooltip = header.getAttribute("title");
+    is(buttonText, tooltip,
+       "The " + header.id + " header has the button text in its 'title' attribute.");
+  }
+
+  yield teardown(monitor);
+});
diff --git a/devtools/client/netmonitor/test/browser_net_sort-01.js b/devtools/client/netmonitor/test/browser_net_sort-01.js
index e49d02d5e3c3..cea0bc1ed24a 100644
--- a/devtools/client/netmonitor/test/browser_net_sort-01.js
+++ b/devtools/client/netmonitor/test/browser_net_sort-01.js
@@ -117,15 +117,19 @@ add_task(function* () {
       if (header != target) {
         ok(!header.hasAttribute("data-sorted"),
           "The " + header.id + " header does not have a 'data-sorted' attribute.");
-        ok(!header.getAttribute("title"),
-          "The " + header.id + " header does not have a 'title' attribute.");
+        ok(!header.getAttribute("title").includes(L10N.getStr("networkMenu.sortedAsc")) &&
+          !header.getAttribute("title").includes(L10N.getStr("networkMenu.sortedDesc")),
+          "The " + header.id +
+          " header does not include any sorting in the 'title' attribute.");
       } else {
         is(header.getAttribute("data-sorted"), direction,
           "The " + header.id + " header has a correct 'data-sorted' attribute.");
-        is(header.getAttribute("title"), direction == "ascending"
+        const sorted = direction == "ascending"
           ? L10N.getStr("networkMenu.sortedAsc")
-          : L10N.getStr("networkMenu.sortedDesc"),
-          "The " + header.id + " header has a correct 'title' attribute.");
+          : L10N.getStr("networkMenu.sortedDesc");
+        ok(header.getAttribute("title").includes(sorted),
+          "The " + header.id +
+          " header includes the used sorting in the 'title' attribute.");
       }
     }
   }
diff --git a/devtools/client/netmonitor/test/browser_net_sort-02.js b/devtools/client/netmonitor/test/browser_net_sort-02.js
index dc230f63fb77..9ae08eac88bc 100644
--- a/devtools/client/netmonitor/test/browser_net_sort-02.js
+++ b/devtools/client/netmonitor/test/browser_net_sort-02.js
@@ -208,15 +208,19 @@ add_task(function* () {
       if (header != target) {
         ok(!header.hasAttribute("data-sorted"),
           "The " + header.id + " header does not have a 'data-sorted' attribute.");
-        ok(!header.getAttribute("title"),
-          "The " + header.id + " header does not have a 'title' attribute.");
+        ok(!header.getAttribute("title").includes(L10N.getStr("networkMenu.sortedAsc")) &&
+          !header.getAttribute("title").includes(L10N.getStr("networkMenu.sortedDesc")),
+          "The " + header.id +
+          " header does not include any sorting in the 'title' attribute.");
       } else {
         is(header.getAttribute("data-sorted"), direction,
           "The " + header.id + " header has a correct 'data-sorted' attribute.");
-        is(header.getAttribute("title"), direction == "ascending"
+        const sorted = direction == "ascending"
           ? L10N.getStr("networkMenu.sortedAsc")
-          : L10N.getStr("networkMenu.sortedDesc"),
-          "The " + header.id + " header has a correct 'title' attribute.");
+          : L10N.getStr("networkMenu.sortedDesc");
+        ok(header.getAttribute("title").includes(sorted),
+          "The " + header.id +
+          " header includes the used sorting in the 'title' attribute.");
       }
     }
   }