["European Journal of Education, Volume 61, Issue 2, June 2026. ", "\nABSTRACT\nGraduate Teaching Assistants (GTAs) play a crucial role in higher education, yet their teaching experiences remain underexplored. This study addresses this gap by examining the construct of integrated identity, which is essential for teachers' effective functioning and wellbeing. An identity is considered integrated when it aligns with an individual's personal values, beliefs, and inclinations. Drawing on Self‐Determination Theory, which emphasises the key role of three basic psychological needs—autonomy, relatedness, and competence—in identity development, the study specifically examines how satisfaction of relatedness and competence needs contributes to GTAs' identity formation. Data were collected from 176 GTAs across UK universities via an online questionnaire and supplemented by semi‐structured interviews with 25 participants. Results indicate generally high levels of need satisfaction, although some frustrations were also reported. The reasons behind GTAs' satisfaction and frustration suggest the development of introjected rather than integrated identities. This research contributes to the underexplored field of GTA professional identity, providing insights into factors that support or hinder integrated identity formation and offering evidence‐based recommendations for enhancing GTA professional development.\n"]