This study sought to describe latent transitions in developmentally and culturally salient interpersonal stressors from late childhood to late adolescence and examine whether different transition patterns predicted early adult mental health problems. Data from four waves (Grades 5, 7, 10, 12) of a study of 749 U.S. Mexican-origin youth were used for a latent transition analysis (LTA) of family, peer, and community stressors; distal outcomes of externalizing and internalizing problems were measured 5 years after Grade 12. Latent class analysis (LCA) and LTA were conducted for investigating underlying subgroups of interpersonal stress at each wave and transitions between subtypes over waves. For the LCA, two latent classes emerged at all four waves, representing low and high interpersonal stress. The LTA model with two classes at all waves was conducted with good fit. Six prominent transition classes emerged and related to young adult internalizing and externalizing problems. Transition class related to young adult internalizing and externalizing problems, such that youth who consistently had exposure to interpersonal stress or who had transitions from low to high exposure had more internalizing and externalizing problems. Findings are discussed relative to the developmental salience of these transitions and opportunities to intervene during adolescence to mitigate later mental health problems. (PsycInfo Database Record (c) 2024 APA, all rights reserved).