The digital media landscape is rapidly shifting, and some children begin using digital media in infancy. As with book reading, young children need adult guidance to learn from digital media. Joint media engagement (JME) occurs when preschool children and their parents actively use digital media together. JME during early childhood is associated with increased learning from media. However, there are no validated scales of JME. In the present study, parents of 353 1-to-5-year olds answered a series of questions about their media use and behaviours. Exploratory factor analysis yielded two scales, one for viewing video content together and one for playing digital games together. Convergent validity was established by comparison to the widely used Television Mediation Scale. Together, these findings establish the JME instrument as a valid and reliable tool for measuring joint media engagement during early childhood.