Due to the sociopolitical culture, LGBTQ+ people experience systemic oppression and discrimination, which impacts screening, assessment, and case conceptualization. LGBTQ+ people are frequently overpathologized and stigmatized in mental healthcare settings, including being provided highly stigmatizing and inaccurate diagnoses. In this chapter, we provide strategies on how to provide person-centered, collaborative, and affirming assessment and case conceptualization using an assessment approach called Collaborative/Therapeutic Assessment. Collaborative/Therapeutic Assessment focuses on addressing the questions the client has about themself and working collaboratively to select assessment materials to address these questions. In this chapter we review Collaborative/Therapuetic Assessment strategies and apply them to a case example to demonstrate person-centered assessment and case conceptualization with an LGBTQ+ client. Lastly, we provide recommendations for future research and practice on screening, assessment, and case conceptualization among LGBTQ+ people.