Data from groups often have a multimember multigroup (MMMG) structure. Examples are two‐parent families with a female or male child (three members, two groups), two same‐gender and opposite‐gender peers of different status (two members, four groups), or gay, lesbian, and heterosexual couples (two members, three groups). To analyze such data, a framework called MMMG actor–partner interdependence model (MMMG APIM) is presented considering group composition. Three models are discussed in detail: the three‐member two‐group APIM, the two‐member four‐group APIM, and the two‐member three‐group APIM. Structural equation modeling and cross‐sectional and longitudinal data are used to illustrate the approach. To ease the interpretation of APIM findings, a proposal of a general classification scheme is made.