This paper explores the foundational role of play in the constitution of the social, showing a way for considering play not merely as a children’s pastime or simply unproductive and pleasurable activity, but a critical component of social relationality and agency. Drawing on anthropological and sociological perspectives, the paper follows an alternative to existing approaches in social robotics, and proposes a conception of ‘Robo Ludens’ through a discussion of play as an attitude that is fundamental to emergence of sociality (Huizinga, 1949), and thus prepare a way for social robotics to explore how to make robots compellingly social. The paper considers play’s inherent ability to invoke indeterminacy (Malaby, 2009), and its facilitation of metacommunication amongst actors that ultimately facilitate their agency and socialization in a given environment (Bateson, 1955). Then a robotic design paradigm proposed by Ralf Der and Georg Martius (2012) is given as an example of how searching for playful attitudes in robots creates dynamic systems that playfully learn and socialize into their environment.