Socioeconomic status (SES) is strongly related to parental behaviors and the quality of parent-child interactions. We examined whether through maternal behaviors, SES is linked to joint attention (JA), an important form of parent-child interactions predicting language development. At 12 months, 50 mother-infant dyads were video-recorded during 5-min free play. We coded for maternal behaviors (sensitivity, cognitive stimulation, positive affect, negative affect, control) and JA characteristics (frequency, duration, initiated by maternal following/directing, passive/coordinated, terminated by mother/infant). Mediation analyses showed that higher-SES mothers were more sensitive, less controlling, provided more cognitive stimulation, and displayed more positive affect resulting in JA interactions of higher quality (e.g., initiated by maternal following rather than directing infant's attention) and quantity (i.e., more time spent in JA). These findings contribute to current literature by revealing maternal behaviors as a mediator between SES and mother-infant JA interactions.