diff --git a/src/gl-matrix/mat2d.js b/src/gl-matrix/mat2d.js
index b6dc5250..47678809 100644
--- a/src/gl-matrix/mat2d.js
+++ b/src/gl-matrix/mat2d.js
@@ -226,6 +226,27 @@ export function rotate(out, a, rad) {
   return out;
 }
 
+/**
+ * Skew (shear) a mat2d by the given angle
+ *
+ * @param {mat2d} out the receiving matrix
+ * @param {mat2d} a the matrix to skew
+ * @param {Number} rad the angle to skew the matrix by
+ * @param {Number} rad the angle to skew the matrix by
+ * @returns {mat2d} out
+ */
+export function skew(out, a, radX, radY) {
+  let x = Math.tan(radX);
+  let y = Math.tan(radY);
+  out[0] = a[0];
+  out[1] = a[1] + x;
+  out[2] = a[2] + y;
+  out[3] = a[3];
+  out[4] = a[4];
+  out[5] = a[5];
+  return out;
+}
+
 /**
  * Scales the mat2d by the dimensions in the given vec2
  *