Purpose: To identify effective teaching strategies for cultivating ethical sensitivity and judgment in undergraduate nursing, given the daily ethical dilemmas of clinical practice and the continued reliance on lecture-based ethics education in Korea. Methods: A systematic review of international studies (2015–2025) was conducted using PubMed, CINAHL, Embase, and the Cochrane Library. Eligible studies addressed undergraduate nursing ethics education, reported learning outcomes, and detailed instructional strategies. Data were extracted on strategy type and outcome measures, and synthesized narratively with attention to comparators. Results: Twenty-five studies frequently employed simulation (e.g., standardized patients, ethics committees with structured debriefing), problem-based learning, e-learning, and blended formats. Across studies, these active approaches improved ethical awareness, empathy, moral sensitivity, decision-making, and judgment, with greater gains where scenarios were authentic, feedback was structured, and interaction was high. Lecture-only formats rarely produced comparable effects. Few studies reflected Korean programs, where pedagogical variety remains limited. Conclusion: Active, practice-oriented strategies show advantages over lectures for developing ethical competence in nursing students. Korean curricula should diversify pedagogy, invest in faculty development for simulation/debriefing and case facilitation, and adopt structured evaluation tools aligned with clinical ethics. Future work should standardize measures and test feasibility in local contexts.