Music theater performances (MTPs) in the early years provide stimulating environments for babies and their caregivers and have spawned intriguing questions about babies’ ability to be engaged in different modalities of art. The aim of this study was to assess babies’ engagement in an MTP designed for children aged 0–3. A video microanalysis of recordings of eight babies, who attended performances of AliBaBach by Companhia de Música Teatral, was made through a coding system designed to quantify a set of behaviors that indicated engagement. The videos were coded on a 1-s time base for (a) babies’ engagement with the performance, caregiver, environment, and self-engagement and (b) five indicators of engagement with the performance: gaze at the performance, positive affect, negative affect, vocalizations, and body movements. The results indicate that engagement with the performance was the most prevalent type of babies’ engagement (62%). The most prevalent indicator of engagement with the performance was gaze. These results suggest that babies were highly engaged in the performances, mostly through visual attention. Babies’ engagement was more evident in scenes that were narratively structured, scenes that were based on musical repetition, and scenes that sped up.