diff --git a/toolkit/components/places/Bookmarks.jsm b/toolkit/components/places/Bookmarks.jsm
index db03fb309273..75e2a0d6de1c 100644
--- a/toolkit/components/places/Bookmarks.jsm
+++ b/toolkit/components/places/Bookmarks.jsm
@@ -1228,7 +1228,12 @@ const VALIDATORS = Object.freeze({
       return new URL(v.spec);
     return v;
   },
-  keyword: simpleValidateFunc(v => typeof(v) == "string" && /^\S*$/.test(v)),
+  keyword: v => {
+    simpleValidateFunc(val => typeof(val) == "string" && /^\S*$/.test(val))
+                      .call(this, v);
+    // Keywords are handled as case-insensitive.
+    return v.toLowerCase();
+  }
 });
 
 /**
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js
index 039bdfb662c0..ce8bfdb7ffb9 100644
--- a/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js
@@ -329,6 +329,7 @@ add_task(function* fetch_bykeyword() {
   Assert.equal(bm2.url.href, "http://bykeyword1.com/");
   Assert.equal(bm2.keyword, "bykeyword");
 
+  // Add a second url using the same keyword.
   let bm3 = yield PlacesUtils.bookmarks.insert({ parentGuid: PlacesUtils.bookmarks.unfiledGuid,
                                                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
                                                  url: "http://bykeyword2.com/",
@@ -352,6 +353,16 @@ add_task(function* fetch_bykeyword() {
   Assert.equal(gAccumulator.results.length, 2);
   gAccumulator.results.forEach(checkBookmarkObject);
   Assert.deepEqual(gAccumulator.results[0], bm5);
+
+  // Check fetching by keyword is case-insensitive.
+  let bm6 = yield PlacesUtils.bookmarks.fetch({ keyword: "ByKeYwOrD" },
+                                              gAccumulator.callback);
+  checkBookmarkObject(bm6);
+  // Cannot use deepEqual cause lastModified changed.
+  Assert.equal(bm1.guid, bm6.guid);
+  Assert.equal(gAccumulator.results.length, 2);
+  gAccumulator.results.forEach(checkBookmarkObject);
+  Assert.deepEqual(gAccumulator.results[0], bm6);
 });
 
 function run_test() {
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js
index d477aa8e117d..de728aea7d98 100644
--- a/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js
@@ -243,10 +243,11 @@ add_task(function* create_bookmark() {
   let parent = yield PlacesUtils.bookmarks.fetch({ guid: bm.parentGuid });
   Assert.deepEqual(parent.lastModified, bm.dateAdded);
 
+  // While here, also check keywords are case-insensitive.
   bm = yield PlacesUtils.bookmarks.insert({ parentGuid: parentGuid,
                                             type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
                                             url: NetUtil.newURI("http://example.com/"),
-                                            keyword: "test" });
+                                            keyword: "tEsT" });
   checkBookmarkObject(bm);
   Assert.equal(bm.parentGuid, parentGuid);
   Assert.equal(bm.index, 1);
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js
index 9491a4d39037..cff76962b411 100644
--- a/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js
@@ -75,9 +75,11 @@ add_task(function* insert_bookmark_keyword_notification() {
   let bm = yield PlacesUtils.bookmarks.insert({ type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
                                                 parentGuid: PlacesUtils.bookmarks.unfiledGuid,
                                                 url: new URL("http://example.com/"),
-                                                keyword: "kw" });
+                                                keyword: "Kw" });
   let itemId = yield PlacesUtils.promiseItemId(bm.guid);
   let parentId = yield PlacesUtils.promiseItemId(bm.parentGuid);
+  // Keywords are case-insensitive.
+  Assert.equal(bm.keyword, "kw");
   observer.check([ { name: "onItemAdded",
                      arguments: [ itemId, parentId, bm.index, bm.type,
                                   bm.url, null, bm.dateAdded,
@@ -173,7 +175,9 @@ add_task(function* update_bookmark_keyword() {
                                                 parentGuid: PlacesUtils.bookmarks.unfiledGuid,
                                                 url: new URL("http://keyword.example.com/") });
   let observer = expectNotifications();
-  bm = yield PlacesUtils.bookmarks.update({ guid: bm.guid, keyword: "kw" });
+  bm = yield PlacesUtils.bookmarks.update({ guid: bm.guid, keyword: "kW" });
+  // Keywords are case-insensitive.
+  Assert.equal(bm.keyword, "kw");
   let itemId = yield PlacesUtils.promiseItemId(bm.guid);
   let parentId = yield PlacesUtils.promiseItemId(bm.parentGuid);
 
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js
index f4c986ec1035..54048df4e4f6 100644
--- a/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js
@@ -90,13 +90,14 @@ add_task(function* remove_bookmark_orphans() {
                                                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
                                                  url: "http://example.com/",
                                                  title: "a bookmark",
-                                                 keyword: "test"});
+                                                 keyword: "tEsT"});
   checkBookmarkObject(bm1);
   PlacesUtils.annotations.setItemAnnotation((yield PlacesUtils.promiseItemId(bm1.guid)),
                                             "testanno", "testvalue", 0, 0);
 
   let bm2 = yield PlacesUtils.bookmarks.remove(bm1.guid);
   checkBookmarkObject(bm2);
+  // Keywords are case-insensitive.
   Assert.equal(bm2.keyword, "test");
 
   // Check there are no orphan keywords or annotations.
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js
index d74dbc79cc41..a6af9072f939 100644
--- a/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js
@@ -248,12 +248,14 @@ add_task(function* update_keyword() {
   let lastModified = bm.lastModified;
 
   bm = yield PlacesUtils.bookmarks.update({ guid: bm.guid,
-                                            keyword: "kw2" });
+                                            keyword: "KW2" });
   checkBookmarkObject(bm);
   Assert.ok(bm.lastModified >= lastModified);
+  // Keywords are case-insensitive.
   Assert.equal(bm.keyword, "kw2");
 
   bm = yield PlacesUtils.bookmarks.fetch(bm.guid);
+  // Keywords are case-insensitive.
   Assert.equal(bm.keyword, "kw2");
   lastModified = bm.lastModified;