Joint attention (JA) has been found to correlate with many developmental outcomes. However, little is known about how naturalistic JA is established and develops during early infancy. In this study, free-flowing tabletop toy play between infants at 5 and 15 months and their mothers (N = 48 dyads; 65% white) was observed to (1) examine changes in JA, (2) investigate whether infants become better leaders or followers of JA, and (3) explore the role of intentionally mediated forms of communication. JA episodes increased in frequency and duration, and initiations of JA became more evenly distributed between members of the dyad. Older infants became better at leading as well as following their mothers' attention behaviors and more frequently directed their attention towards their partner, though this had minimal impact on the organization of episodes of JA.