Behavioural synchronization is adaptive, increasing social cohesion between group members. In humans, affiliation is linked with a high level of synchronization, and individuals prefer people who synchronize with them. Studying those phenomena at interspecific level is essential to better understand the respectives roles of ontogeny and evolution. Here, we review recent findings on behavioural synchronization between dogs and humans and the role of affiliation in it: as in humans, i. affiliation affects the degree of synchronization of dogs towards humans; ii. and dogs prefer people who synchronize with them. To conclude, we have evidenced in dogs a new social process similiar to what is found in humans. We can say that as in humans, behavioural synchronization is a social glue between dogs and humans. Mechanisms at play and implications of the findings are discussed.