This study examined the experiences of Canadian undergraduate students accessing mental healthcare between November 2022 to February 2023. We specifically assessed the impact of social determinants of health (i.e., gender, socioeconomic status, immigration status, English as a second language). Participants were recruited through social media platforms and by undergraduate program administrators at Canadian universities. Participants were asked to provide demographic information, answer questions about their experiences accessing mental healthcare, and to complete the mental health continuum short form (MHC-SF). Descriptive statistics and linear regression models were used to assess the association between MHC-SF and social determinants of health (e.g.: demographics, language, immigration status). Of 1098 students invited to participate, 365 participants completed the study (completion rate: 33.2%). Their mean age (SD) was 21.4 (4.6) years; 73.6% were female and 45.7% identified as non-White. Overall, the mean (SD) MHC-SF score of participants was 2.36 (0.99) out of 5. Students with low SES had lower MHC-SF scores (mean 2.08 vs 2.45; p = 0.003). The multivariable analysis showed that low SES (β -0.36; 95%CI: -0.60 to -0.12) and female gender (β -0.29; 95%CI: -0.58 to -0.012) were associated with lower MHC-SF scores. Additionally, being White was associated with higher MHC-SF scores (β -0.29; 95%CI: -0.44 to 0.54). Age, English as a second language, and immigration status were not significant predictors of mental health. High levels of stress, negative perceptions of the mental healthcare system, and limited access were the more common reported themes in the qualitative analysis. In our cohort, university students from across Canada had low MHC scores. Social determinants of health (e.g., low SES, being non-White, and identifying as a woman) were independent predictors of low MCH scores. Further studies are needed to identify specific groups at higher risk as well as strategies to overcome the suboptimal mental health among Canadian students.