Parental socioeconomic status (SES) strongly influences children's language abilities but less is known about its influence on pragmatic abilities (e.g., inferring intentions from relevance implicatures). Moreover, by focussing on SES, the role of socio-cognitive engagement (e.g., joint parent-child interactions) has been overlooked. We tested four- and six-year-old children (n = 92) with a communication task, a questionnaire assessed parents' SES and socio-cognitive engagement. Socio-cognitive engagement predicted children's communication abilities while the parental educational background and income did not. This emphasizes the notion that communication is a highly socio-cognitive task, one which children perform the better the more frequently they engage in socio-cognitive interactions.