School or academic achievement is a relevant topic of study, as it is evidence of the learning achieved by the student. This study aims to explore a model explaining academic achievement while testing the mediator role of learning strategies, study habits and study attitudes. Research design was correlational. 1712 Dominican students from 12 to 20 years old (52.75% female) were sampled through cluster sampling. Data was recruited with a set of validated questionnaires, including measures of academic achievement (marks), learning strategies, study habits, and attitudes toward studies, school engagement, and academic support. Structural Equation Modeling was used to establish and test the mediational model. Main results show that learning strategies and study habits and attitudes play a mediator role between background variables as age, gender, cognitive or behavioral engagement, and students' academic achievement. Learning strategies and study habits play a central role in achieving a good academic performance, by mediating the effects of academic support and school engagement.