•Efforts to promote early family math engagement are growing.•We conducted a systematic review of research on family math engagement.•Findings highlight strengths and gaps in ongoing family math engagement work.•We propose a broader family math framework that incorporates sociocultural context.•We provide directions for future family math work, emphasizing equity and inclusion. Young children’s math learning opportunities in families appear to relate to long-term math achievement and attitudes. While there is growing interest in promoting families’ support of children’s math learning, existing family math models do not fully capture sources of variation in how families support early math learning. We propose an expanded conceptual framework incorporating macrosystem and mesosystem dimensions, along with developmental considerations, that may influence family math engagement and children’s math learning. We use this framework to guide a systematic review on family math engagement from birth through early elementary school. Reviewing 194 articles from peer-reviewed journals, we asked three questions: 1) How do different aspects of family engagement relate to math outcomes? 2) What accounts for variation in family math engagement? and 3) What evidence is there for effective intervention approaches to support family math engagement? Building on prior models, we identify five facets of family engagement associated with children’s math learning, including math attitudes and expectations, math activities, math talk, the general home learning environment, and school involvement. We also identified sociocultural differences in family math engagement linked to race, ethnicity, socioeconomic status, and gender. Finally, family math intervention studies showed some short-term, but limited long-term, benefits to math engagement and children’s math learning. Our review also identified gaps in the family math engagement literature, particularly in understanding family math engagement across contexts and development. We use our expanded framework to propose future research considering sociocultural, community, and developmental dimensions of family math engagement.