diff --git a/assert/assertions.go b/assert/assertions.go
index 166f63726..1ea3cdba0 100644
--- a/assert/assertions.go
+++ b/assert/assertions.go
@@ -1497,8 +1497,12 @@ func InDeltaSlice(t TestingT, expected, actual interface{}, delta float64, msgAn
 	actualSlice := reflect.ValueOf(actual)
 	expectedSlice := reflect.ValueOf(expected)
 
-	for i := 0; i < actualSlice.Len(); i++ {
-		result := InDelta(t, actualSlice.Index(i).Interface(), expectedSlice.Index(i).Interface(), delta, msgAndArgs...)
+	if actualSlice.Len() != expectedSlice.Len() {
+		return Fail(t, fmt.Sprintf("Lengths of slices must be equal: expected %d, got %d", expectedSlice.Len(), actualSlice.Len()), msgAndArgs...)
+	}
+
+	for i := 0; i < expectedSlice.Len(); i++ {
+		result := InDelta(t, expectedSlice.Index(i).Interface(), actualSlice.Index(i).Interface(), delta, msgAndArgs...)
 		if !result {
 			return result
 		}
diff --git a/assert/assertions_test.go b/assert/assertions_test.go
index 11642e096..38f37d4f0 100644
--- a/assert/assertions_test.go
+++ b/assert/assertions_test.go
@@ -2360,6 +2360,8 @@ func TestInDeltaSlice(t *testing.T) {
 		0.1), "{1, NaN, 2} is not element-wise close to {0, NaN, 3} in delta=0.1")
 
 	False(t, InDeltaSlice(mockT, "", nil, 1), "Expected non numeral slices to fail")
+	False(t, InDeltaSlice(mockT, []float64{1.0, 2.0, 3.0}, []float64{1.0, 2.0}, 0.1), "Expected different length slices to fail")
+	False(t, InDeltaSlice(mockT, []float64{1.0, 2.0}, []float64{1.0, 2.0, 3.0}, 0.1), "Expected different length slices to fail")
 }
 
 func TestInDeltaMapValues(t *testing.T) {