This paper presents a small-scale Critical Participatory Action Research (CPAR) study, investigating school leaders' efforts to enhance families' engagement in their children's learning, through classroom teachers' use of social media. The study occurred within three Australian primary schools, situated within a culturally and linguistically diverse community. Throughout two action research cycles the participating school leaders and classroom teachers critically reflected on family survey data and a sample of social media posts depicting student learning, so as to identify opportunities for enhanced family engagement. A practice lens was used to examine the sayings (words and language), doings (activities and resources) and relatings (relationships and power dynamics) featured within social media posts, to facilitate the participating leaders' critical self-reflection of current practice. Data were collected through surveys, semi-structured interviews, transcripts of reflective practice meetings and reflective practice tools utilised throughout the CPAR process. Analysis of practice architectures identified systemic features utilised by school leaders to support classroom teachers' practice change. Furthermore, this study highlights the significant role that school leaders have in facilitating classroom teachers' use of social media for family engagement.