Reports of variability in the social behavior of the domestic dog (Canis lupus familiaris) are common across populations, breeds, and individuals. This has often been considered a challenge for characterizing the nature and origins of the domestic dog’s social cognition. Here, we propose that this variability might be explained by social plasticity, a trait that could contribute to the success of the domestic dog and facilitate the dog-human bond. Additional research specifically aimed at investigating population and individual variation in canine social behavior, such as attachment-style research, may provide important insight into domestic dogs’ biological success, as well as knowledge that could benefit both dogs and humans in a wide range of applied settings.