Lean production has become deeply institutionalized in the US manufacturing field, which is characterized by the dominance of two institutional logics of operational practice: a detailed package of lean manufacturing practices; and a high-road model of teamwork based on substantive employee involvement. Together, these logics specify acomplementary package of practices widely considered to define world-classmanufacturing and broadly adopted in American management discourse and practice. Based on interviews with 109 individuals and additional ethnographic observation in 31 firms, I find managers systematically deviating from one or both of the dominant logics. This raises a theoretical puzzle: In a competitive market, with a clearly-specified dominant institutional logic of high-involvement lean, understood as best-practice andwell-known to all managers, how do we explain the persistence of diverse organizational forms? The manufacturing field is institutionalized such that there are few enforcement mechanisms associated with the dominant logics, making them effectively normativeprescriptions. As managers confront the new logics in concrete practice, they bring to bear background knowledge and understanding based on past and present experience. In some cases, depending on their experience and aspiration level, managers define thesituation through cultural frames that rationalize modification of the normative logic.