Unmet or thwarted belonging needs have been implicated in multiple studies of women in engineering in college and in the engineering workforce. A wide range of other challenges that women face in engineering are tightly linked to deficits in belonging. Furthermore, many women face intersectional factors across race and ethnicity that make it even more difficult to belong. This literature review looks at women's struggles in engineering in the context of the fundamental psychological need to belong. Studies that investigate belonging are reviewed, as are major contributors to unmet or thwarted belonging including gender identity threat and normative and numerical male dominance. Belonging is not the only psychological need that is inadequately met for women in engineering, but it is a common factor in multiple contexts and the situation worsens as women progress in their career pathways. Studies of belonging among women in engineering underscore the importance of supporting women in fulfilling this basic need even when the cultural transformation of engineering into a gender-balanced environment is not yet a reality.