The study of Key Account Management (KAM) is ubiquitous in business-to-business marketing research. Despite its importance within B2B research, however, few authors have questioned why actors may actually resist its adoption. In a novel 18-month longitudinal ethnographic study following one organization’s endeavours to implement KAM (Fitcorp), we examine the approaches adopted by organizational members to resist KAM implementation. Our understanding of how and why actors might resist KAM implementation reveals a continuum of resistance strategies that vary in severity (spanning disengagement to hostility). Further, we find a number of explanations actors draw on to justify their resistance to KAM implementation. These findings are discussed and implications for theory and practice are offered.