Meaningful cross‐cultural application of family therapy theories requires that basic assumptions about normal family functioning be made explicit, and contextual factors be incorporated into the theories. Guided by this understanding, this article examines the family structure dimensions of proximity and generational hierarchy theoretically and empirically. These dimensions and their superordinate construct, boundary permeability, are analyzed in terms of their underlying assumptions. The cross‐cultural validity of the dimensions is assessed using videotaped interactions, projective drawings, and interviews with a sample of 24 Turkish families. Results indicate that proximity is a valid dimension, moderated by the demographic variables of socioeconomic status (SES), mother's working status, family size, and clinical status. Hierarchy is not a valid dimension because the cultural norm of strong hierarchy suppresses variation. The implications for the cross‐cultural transfer of family therapy theories are disc