diff --git a/esutil/bulk_indexer.go b/esutil/bulk_indexer.go
index 5ed206e9f6..03453d9cfe 100644
--- a/esutil/bulk_indexer.go
+++ b/esutil/bulk_indexer.go
@@ -570,29 +570,24 @@ func (w *worker) flush(ctx context.Context) error {
 	res, err := req.Do(ctx, w.bi.config.Client)
 	if err != nil {
 		atomic.AddUint64(&w.bi.stats.numFailed, uint64(len(w.items)))
-		if w.bi.config.OnError != nil {
-			w.bi.config.OnError(ctx, fmt.Errorf("flush: %s", err))
-		}
-		return fmt.Errorf("flush: %s", err)
+		err := fmt.Errorf("flush: %w", err)
+		w.handleError(ctx, err)
+		return err
 	}
 	if res.Body != nil {
 		defer res.Body.Close()
 	}
 	if res.IsError() {
 		atomic.AddUint64(&w.bi.stats.numFailed, uint64(len(w.items)))
-		// TODO(karmi): Wrap error (include response struct)
-		if w.bi.config.OnError != nil {
-			w.bi.config.OnError(ctx, fmt.Errorf("flush: %s", res.String()))
-		}
-		return fmt.Errorf("flush: %s", res.String())
+		err := fmt.Errorf("flush: %s", res.String())
+		w.handleError(ctx, err)
+		return err
 	}
 
 	if err := w.bi.config.Decoder.UnmarshalFromReader(res.Body, &blk); err != nil {
 		// TODO(karmi): Wrap error (include response struct)
-		if w.bi.config.OnError != nil {
-			w.bi.config.OnError(ctx, fmt.Errorf("flush: %s", err))
-		}
-		return fmt.Errorf("flush: error parsing response body: %s", err)
+		w.handleError(ctx, fmt.Errorf("flush: %w", err))
+		return fmt.Errorf("flush: error parsing response body: %w", err)
 	}
 
 	for i, blkItem := range blk.Items {
@@ -638,6 +633,21 @@ func (w *worker) flush(ctx context.Context) error {
 	return err
 }
 
+func (w *worker) notifyItemsOnError(ctx context.Context, err error) {
+	for _, item := range w.items {
+		if item.OnFailure != nil {
+			item.OnFailure(ctx, item, BulkIndexerResponseItem{}, err)
+		}
+	}
+}
+
+func (w *worker) handleError(ctx context.Context, err error) {
+	if w.bi.config.OnError != nil {
+		w.bi.config.OnError(ctx, err)
+	}
+	w.notifyItemsOnError(ctx, err)
+}
+
 type defaultJSONDecoder struct{}
 
 func (d defaultJSONDecoder) UnmarshalFromReader(r io.Reader, blk *BulkIndexerResponse) error {
diff --git a/esutil/bulk_indexer_internal_test.go b/esutil/bulk_indexer_internal_test.go
index da3a4463bc..9f4d81970d 100644
--- a/esutil/bulk_indexer_internal_test.go
+++ b/esutil/bulk_indexer_internal_test.go
@@ -572,6 +572,133 @@ func TestBulkIndexer(t *testing.T) {
 		}
 	})
 
+	t.Run("TooManyRequests - Fail", func(t *testing.T) {
+		var (
+			wg       sync.WaitGroup
+			numItems = 2
+		)
+
+		esCfg := elasticsearch.Config{
+			Transport: &mockTransport{
+				RoundTripFunc: func(*http.Request) (*http.Response, error) {
+					return &http.Response{
+						StatusCode: http.StatusTooManyRequests,
+						Status:     "429 TooManyRequests",
+						Body:       io.NopCloser(strings.NewReader(`{"took":1}`)),
+					}, nil
+				},
+			},
+
+			MaxRetries:    5,
+			RetryOnStatus: []int{502, 503, 504, 429},
+			RetryBackoff: func(i int) time.Duration {
+				if os.Getenv("DEBUG") != "" {
+					fmt.Printf("*** Retry #%d\n", i)
+				}
+				return time.Duration(i) * 100 * time.Millisecond
+			},
+		}
+		if os.Getenv("DEBUG") != "" {
+			esCfg.Logger = &elastictransport.ColorLogger{Output: os.Stdout}
+		}
+		es, _ := elasticsearch.NewClient(esCfg)
+
+		biCfg := BulkIndexerConfig{NumWorkers: 1, FlushBytes: 28 * 2, Client: es}
+		if os.Getenv("DEBUG") != "" {
+			biCfg.DebugLogger = log.New(os.Stdout, "", 0)
+		}
+
+		bi, _ := NewBulkIndexer(biCfg)
+
+		biiFailureCallbacksCalled := atomic.Uint32{}
+		biiSuccessCallbacksCalled := atomic.Uint32{}
+
+		for i := 1; i <= numItems; i++ {
+			wg.Add(1)
+			go func(i int) {
+				defer wg.Done()
+				err := bi.Add(context.Background(), BulkIndexerItem{
+					Action: "foo",
+					Body:   strings.NewReader(`{"title":"foo"}`),
+					OnFailure: func(ctx context.Context, item BulkIndexerItem, item2 BulkIndexerResponseItem, err error) {
+						_ = biiFailureCallbacksCalled.Add(1)
+						if err == nil {
+							t.Errorf("Unexpected nil error in BulkIndexerItem.OnFailure callback")
+						}
+					},
+					OnSuccess: func(ctx context.Context, item BulkIndexerItem, item2 BulkIndexerResponseItem) {
+						_ = biiSuccessCallbacksCalled.Add(1)
+					},
+				})
+				if err != nil {
+					t.Errorf("Unexpected error: %s", err)
+					return
+				}
+			}(i)
+		}
+		wg.Wait()
+
+		if err := bi.Close(context.Background()); err != nil {
+			t.Errorf("Unexpected error: %s", err)
+		}
+
+		// BulksIndexerItem.OnFailure() callbacks are called for all items.
+		if biiFailureCallbacksCalled.Load() != uint32(numItems) {
+			t.Errorf("Unexpected NumFailedCallbacks: want=%d, got=%d", numItems, biiFailureCallbacksCalled.Load())
+		}
+
+		// BulkIndexerItem.OnSuccess() callbacks are not called.
+		if biiSuccessCallbacksCalled.Load() != 0 {
+			t.Errorf("Unexpected NumSuccessCallbacks: want=%d, got=%d", 0, biiSuccessCallbacksCalled.Load())
+		}
+	})
+
+	t.Run("JSON Decoder Failure", func(t *testing.T) {
+		es, _ := elasticsearch.NewClient(elasticsearch.Config{Transport: &mockTransport{}})
+
+		biFailureCallbacksCalled := atomic.Uint32{}
+		bi, _ := NewBulkIndexer(BulkIndexerConfig{
+			Client: es,
+			Decoder: customJSONDecoder{
+				err: fmt.Errorf("Custom JSON decoder error"),
+			},
+			OnError: func(ctx context.Context, err error) {
+				_ = biFailureCallbacksCalled.Add(1)
+			},
+		})
+
+		biiFailureCallbacksCalled := atomic.Uint32{}
+
+		err := bi.Add(context.Background(), BulkIndexerItem{
+			Action:     "index",
+			DocumentID: "1",
+			Body:       strings.NewReader(`{"title":"foo"}`),
+			OnFailure: func(ctx context.Context, item BulkIndexerItem, item2 BulkIndexerResponseItem, err error) {
+				_ = biiFailureCallbacksCalled.Add(1)
+				if err == nil {
+					t.Errorf("Unexpected nil error in BulkIndexerItem.OnFailure callback")
+				}
+			},
+		})
+		if err != nil {
+			t.Fatalf("Unexpected error, got %s", err)
+		}
+
+		if err := bi.Close(context.Background()); err != nil {
+			t.Errorf("Unexpected error: %s", err)
+		}
+
+		// BulksIndexerItem.OnFailure() callbacks are called only for failed items.
+		if biiFailureCallbacksCalled.Load() != 1 {
+			t.Errorf("Unexpected NumFailedCallbacks: want=%d, got=%d", 1, biiFailureCallbacksCalled.Load())
+		}
+
+		// BulkIndexer.OnError() callbacks are called for all errors.
+		if biFailureCallbacksCalled.Load() != 2 {
+			t.Errorf("Unexpected NumFailedCallbacks: want=%d, got=%d", 2, biFailureCallbacksCalled.Load())
+		}
+	})
+
 	t.Run("Custom JSON Decoder", func(t *testing.T) {
 		es, _ := elasticsearch.NewClient(elasticsearch.Config{Transport: &mockTransport{}})
 		bi, _ := NewBulkIndexer(BulkIndexerConfig{Client: es, Decoder: customJSONDecoder{}})
@@ -926,8 +1053,13 @@ func TestBulkIndexerItem(t *testing.T) {
 	})
 }
 
-type customJSONDecoder struct{}
+type customJSONDecoder struct {
+	err error
+}
 
 func (d customJSONDecoder) UnmarshalFromReader(r io.Reader, blk *BulkIndexerResponse) error {
+	if d.err != nil {
+		return d.err
+	}
 	return json.NewDecoder(r).Decode(blk)
 }