Abstract Objective: Young adulthood is a transitional period between childhood and adulthood characterized by unique stressors that increase the risk of food insecurity and poor mental health. This study examined the association between food insecurity and mental health outcomes among U.S. young adults aged 18-25. Design: A cross-sectional survey was completed by young adults between the ages of 18-25 years between January and April 2022. Key measures included food insecurity, perceived stress, anxiety, depressive symptoms, and insomnia. Descriptive statistics and linear regression analyses were used to determine the prevalence of and associations between food insecurity and mental health outcomes, controlling for key demographic and social factors. Setting: Online survey Participants: 1,630 U.S. young adults Results: Among the analytic sample of 1,041 young adults, nearly 70% of participants identified as being food insecure in the last year. Participants reported moderate to high levels of perceived stress, anxiety, depressive symptoms, and insomnia. Food insecurity was positively associated with each mental health outcome including perceived stress (β=2.28, p<0.01), anxiety (β=2.84, p<0.01), depressive symptoms (β=2.74, p<0.01), and insomnia (β=1.28, p<0.01) after controlling for all other factors. Conclusion: Food insecurity is associated with mental health problems among young adults. Future efforts should explore the directionality of this relationship to determine if food insecurity initiates or exacerbates poor mental health outcomes or if poor mental health contributes to food insecurity. Interventions to improve food security status may also help support mental health among young adults.