Boxing is a cognitively and physically demanding combat sport in which psychological factors frequently determine the outcome of competition. This paper reviews the existing literature on mental toughness (MT) as a predictor of competitive success in boxing. Drawing on more than seven peer-reviewed empirical and theoretical studies, the review examines how MT defined through conceptual frameworks such as the 4Cs model (Clough et al., 2002) and the attributes model (Jones et al., 2002, 2007) relates to anxiety regulation, self-confidence, emotional control, resilience and decision-making under pressure. Evidence consistently demonstrates that elite-level boxers exhibit higher MT than sub-elite competitors and that MT inversely predicts competitive anxiety while positively predicting self-confidence and performance outcomes. The review further explores the role of psychological skills training in cultivating MT and identifies gaps in research specifically targeting amateur and professional boxing populations. Implications for sport psychologists, coaches and athletes are discussed, along with directions for future research.