The purpose of this study is to explore women knowledge workers’ experiences of the intersectionality of the gender pay gap and to scrutinize the reasons behind gender pay gap. The study problematizes the gender pay gap phenomenon by using intersectionality theory. The study describes how the gender pay gap varies based on ethnical differences besides being women and reveals how this situation deinstitutionalizes women’s careers. The study utilized a descriptive qualitative research design employing thematic analysis conducted in Germany and Türkiye with a purposively selected sample of participants. The study’s empirical material was generated through semi-structured interviews with women knowledge workers who differ in ethnicity and generally work in science, technology, engineering, and mathematics (STEM) fields. The study’s findings indicated that ethnicity should be considered among other intersectional factors to analyze the gender pay gap comprehensively. The reasons behind the gender pay gap are found to be the lack of transparency in the workplace, gender-based occupational segregation, culture, the glass ceiling, the existence of male-dominated informal communication channels, and the fact that women workers are more easily preferred in organizational downsizing initiatives.