(1) Background: Medical cannabis (MC) is attracting global attention due to its therapeutic potential; however, the preparedness of nursing students in countries where MC remains banned is not well understood. This convergent parallel mixed-methods study aimed to examine the knowledge, attitudes, beliefs and intention to support the future legalization of MC among Vietnamese nursing students, as well as to identify factors associated with this intention. (2) Methods: A cross-sectional survey was conducted among 422 nursing students selected via simple random sampling at Dong Thap Medical College, Vietnam, alongside in-depth interviews with 10 purposefully selected participants. Data were analyzed using descriptive statistics, ordinal logistic regression, and thematic analysis. (3) Results: Nursing students achieved 56.5% of the maximum knowledge score, while attitude and belief scores were 73.5% and 68.1% of the respective maximums. Notably, 56.2% of students remained undecided about supporting the future legalization of MC. Greater knowledge and stronger beliefs regarding the therapeutic benefits and safety of MC were independently associated with higher intention to support future legalization, whereas general attitudes were not statistically significant in the multivariable model. Four core qualitative themes emerged—therapeutic value, safety and ethical concerns, professional readiness, and social, legal, and organizational impacts—providing rich contextual explanations for the quantitative findings. (4) Conclusions: Intention to support the future legalization of MC depends not only on individual knowledge and beliefs but also on confidence in evidence-based practice, professional preparedness, and regulatory oversight. Integrating education on MC into nursing curricula can enhance future workforce readiness and support evidence-based healthcare policy.

(1) Background: Medical cannabis (MC) is attracting attention globally due to its therapeutic potential; however, the preparedness of nursing students in countries where MC remains banned is limited. The convergent parallel mixed-methods study examined the knowledge, attitudes, beliefs, and intention. (2) Methods: A cross-sectional survey was conducted with 422 nursing students selected through simple random sampling at Dong Thap Medical College, Vietnam, and in-depth interviews were conducted with 10 purposefully selected participants. Descriptive statistics, ordinal logistic regression, and thematic analysis were used in the data analysis. (3) Results: Nursing students demonstrated average knowledge and positive attitudes and beliefs toward MC. Over 50% of students were undecided about supporting MC legalization. Deep knowledge and stronger beliefs about therapeutic benefits and safety were independently associated with higher intention to advocate for MC, while attitudes were not statistically significant. Four themes emerging include therapeutic value, safety and ethical concerns, professional readiness, and social, legal, and organizational impacts, providing contextual explanations for the quantitative results. (4) Conclusion: The adoption of MC is dependent not only on knowledge and beliefs but also on confidence in evidence-based practice, professional readiness, and regulatory oversight. Nursing education on MC can enhance future workforce readiness and support evidence-based healthcare policy.