Objective: to describe the cross-cultural adaptation process of the Positive Mental Health Questionnaire for undergraduate Nursing students, in the Brazilian context. Method: a psychometric study conducted in public universities in Rio de Janeiro/Brazil, between October 2019 and July 2020. The transcultural adaptation process encompassed the following stages: translation; reconciliation; back-translation; independent reviews by a committee of reviewers; pre-completion; completion; harmonization; formatting and review; cognitive test with 31 undergraduate Nursing students from two public universities; and analysis of the comments. Results: the process lasted approximately ten months, and the initial translations, carried out independently by two translators, achieved close versions; none of the translators reported difficulties in translating the meanings of the items. The Brazilian version of the instrument maintained conceptual, semantic, idiomatic, and experimental equivalences. The mean content validity ratio values for clarity, relevance, pertinence, and theoretical dimension were higher than established; the assessment by the target audience showed good understanding. Conclusion: the Positive Mental Health Questionnaire - Brazilian version showed equivalence with the original version, developed in Spain, and presented satisfactory evidence of content validity for use with undergraduate Nursing students in Brazil, being easy-to-understand by the target audience.