diff --git a/assert/assertions.go b/assert/assertions.go
index 166f63726..79224f345 100644
--- a/assert/assertions.go
+++ b/assert/assertions.go
@@ -1497,6 +1497,10 @@ func InDeltaSlice(t TestingT, expected, actual interface{}, delta float64, msgAn
 	actualSlice := reflect.ValueOf(actual)
 	expectedSlice := reflect.ValueOf(expected)
 
+	if expectedSlice.Len() != actualSlice.Len() {
+		return Fail(t, "Parameters must have the same number of elements", msgAndArgs...)
+	}
+
 	for i := 0; i < actualSlice.Len(); i++ {
 		result := InDelta(t, actualSlice.Index(i).Interface(), expectedSlice.Index(i).Interface(), delta, msgAndArgs...)
 		if !result {
diff --git a/assert/assertions_test.go b/assert/assertions_test.go
index 11642e096..a408123f7 100644
--- a/assert/assertions_test.go
+++ b/assert/assertions_test.go
@@ -2360,6 +2360,16 @@ 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, 2},
+		[]float64{1},
+		0.001), "Slices of different lengths should fail even if the common prefix matches")
+
+	False(t, InDeltaSlice(mockT,
+		[]float64{1},
+		[]float64{1, 2},
+		0.001), "Slices of different lengths should fail regardless of which is longer")
 }
 
 func TestInDeltaMapValues(t *testing.T) {