Background: The utilization of a theoretical framework is vital in health promotion research, particularly when endeavoring to modify health behaviors. This systematic review aimed at evaluating and synthesizing evidence through studies conducted using the fourth-generation multi-theory model (MTM) of health behavior change for its effectiveness. Methods: A comprehensive article search was performed across MEDLINE, CINAHL, and Academic Search Premier. The search focused on studies utilizing MTM from 2016 to December 2023, following the PRISMA guidelines for systemic reviews. Results: An initial pool of 7583 articles was narrowed down through screening of titles, abstracts, and full texts. A total of 69 articles met the inclusion criteria. These studies, encompassing a global range of diverse target groups and health behaviors, were categorized as qualitative, cross-sectional, or experimental. The six qualitative studies revealed MTM themes for diverse health behaviors. The fifty-six cross-sectional studies showed MTM constructs effectively predicting behavior change, albeit with varying statistical significance. The seven experiments demonstrated MTM’s role in initiating and sustaining change. For the initiation model, operationalized by 49 studies, the mean adjusted R2 was 38.4% (SD=16.4%). For the sustenance model, operationalized by 45 studies, the mean adjusted R2 was 38.9% (SD=15.5%). Conclusion: This systematic review corroborates the MTM as a potent framework for understanding, predicting, and facilitating health behavior changes. Its universal applicability and effectiveness underscore the model’s potential as a foundational tool in designing future health promotion strategies and interventions aimed at positive and enduring behavior modifications.

Hesitancy toward the COVID-19 vaccine has hindered its rapid uptake among the Hispanic and Latinx populations. The study aimed to use the Multi-Theory Model (MTM) for health behavior change to explain the intention of initiating and sustaining the behavior of COVID-19 vaccination among the Hispanic and Latinx populations that expressed and did not express hesitancy towards the vaccine in Nevada. Using a quantitative cross-sectional and survey-based research study design, data were collected using a 50-item questionnaire and analyzed using multiple linear regression modeling. Of 231 respondents, participatory dialogue (b = 0.113, p < 0.001; b = 0.072, p < 0.001) and behavioral confidence (b = 0.358, p < 0.001; b = 0.206, p < 0.001) displayed significant associations with the initiation of COVID-19 vaccine acceptance among vaccine-hesitant and non-vaccine-hesitant individuals. Emotional transformation (b = 0.087, p < 0.001; b = 0.177, p < 0.001) displayed a significant association with the sustenance of COVID-19 vaccine acceptance among vaccine-hesitant and non-vaccine-hesitant individuals. Results from this study provide evidence that the MTM is a useful tool in predicting COVID-19 vaccine acceptance behavior among Hispanics and Latinxs in Nevada, and it should be used in intervention designs and messaging to promote vaccine uptake.