diff --git a/gglm/transform.go b/gglm/transform.go
index 7807763..cffe40d 100755
--- a/gglm/transform.go
+++ b/gglm/transform.go
@@ -136,7 +136,7 @@ func Ortho(left, right, top, bottom, nearClip, farClip float32) *TrMat {
 		Mat4: Mat4{
 			Data: [4][4]float32{
 				{2 / (right - left), 0, 0, 0},
-				{0, 2 / -(top - bottom), 0, 0},
+				{0, 2 / (top - bottom), 0, 0},
 				{0, 0, -2 / (farClip - nearClip), 0},
 				{-(right + left) / (right - left), -(top + bottom) / (top - bottom), -(farClip + nearClip) / (farClip - nearClip), 1},
 			},