This systematic review synthesises findings from 51 empirical studies on remedial mathematics interventions at the secondary school level. The review analyses interventions across five dimensions: target student population, mathematical content, adaptivity, efficacy, and integration of digital technology. The findings reveal a strong emphasis on foundational skills, particularly arithmetic, algebra, and word problems, with little attention to geometry, statistics, or higher-level mathematical reasoning. Most interventions adopt highly structured and pre-scripted designs, offering limited adaptivity to students' evolving needs. Digital technologies are incorporated in fewer than half of the studies and primarily support procedural learning through video modelling or intelligent tutoring systems, rather than conceptual understanding. Although many interventions report positive short-term outcomes, evidence of long-term effectiveness and responsiveness to learner diversity remains limited. Overall, the review highlights the need for more flexible, theoretically grounded, and technology-enhanced remedial interventions that address conceptual sense-making and support diverse learners within inclusive secondary school contexts.
