Behavioral synchronization is evolutionary adaptive, fostering social cohesion. In humans, affiliation between partners is associated with a high level of behavioral synchronization; people show increased affiliation towards people who synchronize with them. Surprisingly, until recently, little was known about these phenomena at an interspecific level, which is, however, essential to better understand the respective roles of evolution and ontogeny. After presenting why dog-human dyads are a relevant biological model to study this field of social cognition, we review the recent findings about dog-human behavioral synchronization. We summarize recently published findings on behavioral synchronization and affiliation between dogs and humans. We also review results showing that genetic selection modulates behavioral synchronization propensity in dogs, emphasizing the role of genetic selection on dog's social behaviors towards humans. Finally, we discuss the possible evolutionary influences and proximate mechanisms of this phenomenon. We conclude that, as in humans, behavioral synchronization acts as a social glue between dogs and humans. After dogs' ability to use human-directional cues or to produce referential cues towards humans, we evidenced a new human-like social process in the dog, at the interspecfic level with humans.