Adult listeners generally agree on the intended emotion communicated in music, and musical cues are often associated with either the valence or arousal dimension of the target emotion. While music can alter emotional affect as early as infancy, little is known about how identification of musical emotions develops. While studies with adults usually involve scale-based ratings of valence and arousal, studies with children typically use forced-choice tasks with facial expressions or verbal labels. Widen and Russell (2016) recently introduced the Children’s Scales of Pleasure and Arousal (CSPA), which captures valence and arousal ratings of static emotional faces in children as young as three. In the present study, we adapted these scales to investigate children’s perception of musical emotions. We selected musical excerpts from a corpus of film music (Eerola & Vuoskoski, 2011) that differed on valence and arousal as rated by professional adult musicians. Pilot studies conducted in the lab demonstrated that while 5-year-old children (N = 17) were able to effectively use the scales with musical excerpts, 3-year-old children (N =28) were not. In a second study, we adapted the methodology to test 5-year-old children in an online experiment (current N = 24) investigating hypotheses about whether valence or arousal judgments of musical stimuli mature earlier in development. Testing is ongoing, but preliminary results are presented. Results from these two studies indicate the CSPA can be used to bridge the methodological gap in research with young children and adults in this domain.