Background <p>Research has found that first-generation immigrants often experience poorer mental health outcomes than later-generation immigrants and native-born individuals. Perceived discrimination is a key factor, exacerbated by recent global events such as COVID-19. However, much of the literature aggregates immigrants of different Asian ethnicities and generational statuses, despite documented disparities in mental health outcomes. This review aims to address this gap in literature by systematically reviewing empirical studies that explore the relationship between perceived discrimination and mental health outcomes of first-generation immigrants from East Asia only.</p> Methods <p>This review was registered on the PROSPERO international registry for systematic review protocols (Registration Number: CRD42024505188). Five databases (Embase, PsycINFO, Medline, Web of Science and Scopus) were searched for quantitative, English-language studies that explored the relationship between perceived discrimination and validated measures of mental health outcomes among first-generation East Asian immigrants. Studies were appraised for methodological quality using The Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Analytical Cross-Sectional Studies tool [<CitationRef CitationID="CR1">1</CitationRef>]. Findings were synthesised narratively due to heterogeneity in methodology across studies.</p> Results <p>Out of 1,061 screened articles, 10 studies met the inclusion criteria. All included studies explored perceived discrimination, through racial discrimination. Only studies of Korean or Chinese first-generation immigrants were found. Ten studies reported a significant association between perceived racial discrimination and poorer mental health outcomes, particularly depressive symptoms. A range of variables that influenced this relationship were also identified, with degree of social support emerging as a consistent factor. Methodological limitations included inconsistent control for relevant sociodemographic or immigrant-related variables and differences in in exclusion or inclusion criteria used in the different studies.</p> Conclusion <p>Overall, the findings highlight that experiences of perceived racial discrimination have a detrimental impact on the mental health of first-generation Korean and Chinese immigrants. However, inconsistencies in the measurement and study design presented challenges for synthesising the results and drawing firm conclusions, particularly regarding the role of influencing variables. Future research should use more consistent measures of perceived discrimination and mental health to better quantify the outcomes and understand the mental health implications. Research should also continue to disaggregate data by both generational status and specific East Asian ethnic groups, particularly those underrepresented in the current review, such as Japanese, Taiwanese, and Mongolian immigrants.</p>