|Studies of maternal responsiveness suggest responsive maternal utterances may encourage infant behaviors important to mastering speech and language. However, little is known about instances in which mothers are non-responsive. This study examined maternal non-responsive utterances and nonverbal actions in 35 mother-infant dyads when infants were 4, 6, 8, 10, 12, or 14 months old, using a cross-sectional design. Maternal utterances deemed non-responsive to infant vocalizations in this study were divided into five mutually exclusive categories (activity comment, comment on new infant action, game/routine, redirect, and unchanged classification). Maternal nonverbal actions that occurred within 3 seconds of infant vocalizations were also investigated. Responsive nonverbal actions were defined as contingent upon and relevant to the preceding infant vocalization. Maternal actions included head nods, comfort behaviors, object-related behaviors, increased proximity, and repositioning. Maternal actions that occurred with maternal responsive utterances, non-responsive utterances, and silences were investigated. Results revealed mothers often produced activity comments rather than responding to infants' vocalizations directly. Mothers combined responsive actions with responsive or non-responsive utterances more often than with silences; however, object-related responsive but nonverbal actions were common across all categories studied. In conclusion, mothers frequently responded to infant vocalizations with appropriate verbal and nonverbal behaviors.