This article considers how women in a gendered profession, engineering, construct their professional identity in response to workplace interpersonal interactions that marginalize it. Using data from interviews with women engineers, it also explores how these interactions influence the engineers' sense of self and belonging in engineering. The interpersonal interactions place professional identity on the periphery and can overly validate gender identity. I discuss two types of identity construction strategies employed by the participants in response to these marginalizing interactions: impression management tactics and coping strategies. Although the data demonstrate that participants may be left feeling devalued or ambivalent towards their identity or fit in engineering, some interactions are more validating and offer a sense of belonging. This article also reflects on how the engineers' actions may, in fact, represent forces for change in the gendered culture of engineering.