A social identity lens and theories of self-reinforcement are used to explore identity work and processes of identification at the micro-level in a large construction company. Rich data from a qualitative case study show that a strong collective identification is self-defining for the vast majority of managers in the organization, regardless of their role and function. This collective identification revolved around the trade of 'being a construction worker', associated with the traits of being practically oriented and of having a long professional background in construction. This collective identification seems to reinforce itself by a combination of pulling and pushing movements and/or 'being blind' vis-à-vis those that stand outside its self-defining core, content, and behaviours. The results of the study suggest that self-defining at the individual and group levels has implications for organizational performance and outcomes. It is also suggested that the use of a social identity lens can help increase understanding of interpersonal relations, collaboration, and change initiatives in the construction industry.