diff --git a/lodash.js b/lodash.js
index 7e1c33bab..6e208e5a6 100644
--- a/lodash.js
+++ b/lodash.js
@@ -14249,7 +14249,7 @@
       if (isObject(options)) {
         var separator = 'separator' in options ? options.separator : separator;
         length = 'length' in options ? toInteger(options.length) : length;
-        omission = 'omission' in options ? toString(options.omission) : omission;
+        omission = 'omission' in options ? baseToString(options.omission) : omission;
       }
       string = toString(string);
 
@@ -14289,7 +14289,7 @@
           }
           result = result.slice(0, newEnd === undefined ? end : newEnd);
         }
-      } else if (string.indexOf(separator, end) != end) {
+      } else if (string.indexOf(baseToString(separator), end) != end) {
         var index = result.lastIndexOf(separator);
         if (index > -1) {
           result = result.slice(0, index);
diff --git a/test/test.js b/test/test.js
index 02e660b45..915e76e85 100644
--- a/test/test.js
+++ b/test/test.js
@@ -21856,6 +21856,13 @@
       assert.strictEqual(_.truncate(string, { 'omission': ' [...]' }), 'hi-diddly-ho there, neig [...]');
     });
 
+    QUnit.test('should coerce nullish `omission` values to strings', function(assert) {
+      assert.expect(2);
+
+      assert.strictEqual(_.truncate(string, { 'omission': null }), 'hi-diddly-ho there, neighbnull');
+      assert.strictEqual(_.truncate(string, { 'omission': undefined }), 'hi-diddly-ho there, nundefined');
+    });
+
     QUnit.test('should support a `length` option', function(assert) {
       assert.expect(1);