Background The number of immigrants in the United States and the risk of suicide among minoritized individuals have increased. Little research has examined the impact of immigration legal status on suicide-related thoughts and behaviors (SRTB), despite theoretical and empirical work suggesting that feelings of burdensomeness and failure to belong (prominent among immigrants) are risk factors. Methods We examined a diverse sample of foreign-born young adults (18–25; N = 366). Data collection utilized the Suicide Behaviors Questionnaire Revised and items probing belongingness and immigration status (undocumented/Deferred Action for Childhood Arrivals (DACA), permanent, and citizen). Results DACA/undocumented status was associated with increased SRTB compared with permanent and citizen categories. Increased SRTBs were associated with reduced feelings of acceptance in the United States, increased deportation fears, and increased fear of being harassed or hurt. Of these belongingness variables, only the interpersonal—not feeling welcome in the United States—partially mediated the risk relation between DACA/undocumented immigration legal status and SRTBs, whereas physical and legal threat, like deportation, did not. Conclusions Our results highlight the interpersonal nature of SRTB risk in DACA/undocumented immigrants and the need for targeted culture and context-appropriate interventions, as well as advocacy and policy to reduce risk in this historically marginalized population.