Evidence links an athlete’s focus of attention to enhancing strength performance. However, additional research is needed to investigate the applicability of studies beyond the tasks and population currently examined. Therefore, we aimed to systematically review studies concerning attentional focus effects on strength characteristics on lower-limb tasks in athletes. Scopus, Web of Science, and EBSCO databases were searched using Prisma PERSIST guidelines and keywords related to the focus of attention, force production processes, and athletes. Participants were categorized: World-class (Tier 5); Elite (Tier 4); Highly trained (Tier 3); Trained/Developmental (Tier 2); Non-athletes (Tiers 1–0); and Mixed (different levels). Fifteen out of 296 studies met the inclusion criteria. Included studies investigated focus of attention effects: on performance (n = 6), between skill levels (n = 2), for learning (n = 5), with respect to participant preference (n = 1), and one study did not state the aim. Studies achieved an average risk of bias score of ‘Excellent’; however, findings suffered in the assessment of certainty. Only two studies reported an advantage for one type of attentional focus (external focus) across conditions (g = .13–.42) with Tier 2 and Mixed Tier athletes. Research does not address the needs of elite athletes and there is limited evidence on each type of strength characteristics and muscle action. There is also a need to incorporate methodological steps to promote task-relevant instructions. Research should focus on contextualized information within professional practice to offer stronger translational implications for athletes and coaches.