"Why Don't You Know" is a song by South Korean singer Chungha, featuring rapper Nucksal. The song serves as the lead single from her debut EP, Hands on Me.
The music video was released on 6 June 2017, and in the music video for the track, Chungha dances in a vast grassy field, sporting colorful summer outfits. As of January 2019, the music video has surpassed 20 million views on YouTube.