diff --git a/pkg/interpreter/interpreter.go b/pkg/interpreter/interpreter.go
index 0cd0c19..f1a8f8b 100644
--- a/pkg/interpreter/interpreter.go
+++ b/pkg/interpreter/interpreter.go
@@ -121,24 +121,36 @@ func (intr *treeInterpreter) execute(node parsing.ASTNode, value interface{}, fu
 		case parsing.TOKNE:
 			return !util.ObjsEqual(left, right), nil
 		}
-		leftNum, ok := util.ToNumber(left)
-		if !ok {
-			return nil, nil
-		}
-		rightNum, ok := util.ToNumber(right)
-		if !ok {
-			return nil, nil
+		if leftStr, ok := left.(string); ok {
+			if rightStr, ok := right.(string); ok {
+				switch node.Value {
+				case parsing.TOKGT:
+					return leftStr > rightStr, nil
+				case parsing.TOKGTE:
+					return leftStr >= rightStr, nil
+				case parsing.TOKLT:
+					return leftStr < rightStr, nil
+				case parsing.TOKLTE:
+					return leftStr <= rightStr, nil
+				}
+			}
 		}
-		switch node.Value {
-		case parsing.TOKGT:
-			return leftNum > rightNum, nil
-		case parsing.TOKGTE:
-			return leftNum >= rightNum, nil
-		case parsing.TOKLT:
-			return leftNum < rightNum, nil
-		case parsing.TOKLTE:
-			return leftNum <= rightNum, nil
+		if leftNum, ok := util.ToNumber(left); ok {
+			if rightNum, ok := util.ToNumber(right); ok {
+				switch node.Value {
+				case parsing.TOKGT:
+					return leftNum > rightNum, nil
+				case parsing.TOKGTE:
+					return leftNum >= rightNum, nil
+				case parsing.TOKLT:
+					return leftNum < rightNum, nil
+				case parsing.TOKLTE:
+					return leftNum <= rightNum, nil
+				}
+			}
 		}
+		// TODO: don't we want to return an error here ?
+		return nil, nil
 	case parsing.ASTExpRef:
 		return func(data interface{}) (interface{}, error) {
 			return intr.execute(node.Children[0], data, functionCaller)
diff --git a/pkg/interpreter/interpreter_test.go b/pkg/interpreter/interpreter_test.go
index 67c6422..57e9313 100644
--- a/pkg/interpreter/interpreter_test.go
+++ b/pkg/interpreter/interpreter_test.go
@@ -185,6 +185,31 @@ func TestCanSupportProjectionsWithStructs(t *testing.T) {
 	assert.Equal([]interface{}{"first", "second", "third"}, result)
 }
 
+func TestCompareStrings(t *testing.T) {
+	assert := assert.New(t)
+	data := []string{"a", "b", "c"}
+	{
+		result, err := search(t, "@[?@ > 'a']", data)
+		assert.Nil(err)
+		assert.Equal([]interface{}{"b", "c"}, result)
+	}
+	{
+		result, err := search(t, "@[?@ >= 'b']", data)
+		assert.Nil(err)
+		assert.Equal([]interface{}{"b", "c"}, result)
+	}
+	{
+		result, err := search(t, "@[?@ < 'b']", data)
+		assert.Nil(err)
+		assert.Equal([]interface{}{"a"}, result)
+	}
+	{
+		result, err := search(t, "@[?@ <= 'b']", data)
+		assert.Nil(err)
+		assert.Equal([]interface{}{"a", "b"}, result)
+	}
+}
+
 func TestCanSupportSliceOfStructsWithFunctions(t *testing.T) {
 	assert := assert.New(t)
 	data := []scalars{{"a1", "b1"}, {"a2", "b2"}}