There is a long history of research among adolescents who are minoritized and marginalized for their sexual orientation and gender identity/expression (SOGIE). However, it remains unclear how we can best conceptualize and assess SOGIE in adolescence, resulting in different subpopulations and findings across studies. Addressing this issue, we present a narrative literature review of the conceptualization and assessment of SOGIE, and provide recommendations for conceptualizing and operationalizing these concepts. Our review indicated that most research with adolescent populations still almost exclusively assesses isolated dimensions of sexuality and gender (e.g., attraction but not identity). We argue that to make research inclusive and equitable, scholars are required to make clear substantiated decisions and be transparent about the SOGIE dimensions and, thus, subpopulations they represent.