Treatment personalization refers to tailoring treatment to address client characteristics that predict treatment response. Treatment approaches that are flexible by design may be particularly well-suited for treatment personalization. One such approach is modular treatment, which provides a menu of treatment procedures (i.e., a menu of modules) that can be differentially selected and sequenced based on individual client needs. Because of their flexible nature, modular treatments require more clinician decision-making compared to more prescriptive approaches with a predetermined sequence of sessions. Indeed, Venturo-Conerly et al. (2022) find that clinical judgment is the most common decision-making tool for clinicians using modular youth psychotherapies. This commentary briefly reviews relevant literature on a factor associated with clinical judgment, treatment outcomes, and mental health inequities: stigma. Conceptual and empirical recommendations supporting the integration of treatment personalization and stigma are provided, including the efficient adaptation, evaluation, and scaling up of existing evidence-based treatments, and widespread efforts to train clinicians in generalizable culturally- responsive practices.