This paper discusses Scotus’s view of how God knows sins by analyzing texts from his discussions of God’s permission of sin and predestination. I show that Scotus departed from his standard theory of how God knows contingents when explaining how God knows sins. God cannot know sins by knowing a first-order act of his will, as he knows other contingents according to Scotus, since God does not directly will sins. I suggest that Scotus’s recognition that his standard theory of God’s knowledge of contingents could not account for how God knows sins may have contributed to his ultimate rejection of this theory.