<p>Extensive empirical evidence has demonstrated the detrimental impact of childhood psychological maltreatment on psychological functioning in later life. Nevertheless, the protective factors that may mediate these adverse effects over time remain insufficiently explored. A comprehensive understanding of such mechanisms is critical for informing the development of targeted prevention and intervention strategies aimed at mitigating the negative outcomes associated with early maltreatment. This longitudinal study examined the mediating role of optimism and positive self-beliefs in the relationship between childhood psychological maltreatment and psychological symptoms in young adults. The sample comprised 343 Turkish young adults (64% female), aged between 17 and 46 years (<i>M</i> = 21.24, <i>SD</i> = 4.61), who completed online surveys at two time points approximately seven months apart. Structural equation modeling indicated that optimism and positive self-beliefs fully mediated the association between childhood psychological maltreatment and psychological symptoms. Initially, childhood psychological maltreatment was positively associated with psychological symptoms; however, this direct effect became non-significant upon inclusion of the mediators in the model. These findings underscore the critical role of optimism and positive self-beliefs as protective psychological resources that may reduce the long-term adverse effects of childhood psychological maltreatment among young adults.</p>