This disclosure relates to proximity sensing for wink detection. An illustrative method includes receiving data from a receiver portion of a proximity sensor. The receiver portion is disposed at a side section of a head-mountable device (HMD). When a wearer wears the HMD, the receiver portion is arranged to receive light reflected from an eye area of the wearer, the proximity sensor detects a movement of the eye area, and the data represents the movement. The method includes determining that the data corresponds to a wink gesture. The method also includes selecting a computing action to perform, based on the wink gesture. The method further includes performing the computing action.