To better understand what constitutes listening competency, we perform a systematic review of listening scales. Our goal was twofold: to determine the most commonly appearing listening traits and to determine if listening scales are similar to one other. As part of our analysis, we identified 53 relevant scales and analyzed the scales qualitatively and quantitatively. We conclude that the most commonly mentioned listening traits include responding or giving feedback, asking questions, and using nonverbal communication. We also show that the scales are relatively dissimilar, thereby suggesting that researchers have different perspectives on how best to characterize competent listening.