Review question/objective The review objective is to synthesize the best available evidence on the effectiveness of teaching strategies for the development of critical thinking among nursing undergraduate students. The review question is: What is the effectiveness of teaching strategies in promoting the development of critical thinking in undergraduate nursing students? Background In 1991, the National League for Nursing (NLN) identified critical thinking (CT) as a core competency in the practice of nursing.1 Similar to the USA, CT has become a major concern of undergraduate nursing courses, particularly in regards to the way by which professors should instruct their students to think and develop CT. Based on this, the United Nations Educational, Scientific and Cultural Organization (UNESCO, 1998)2 recommends the introduction of innovative educational approaches that enable the development of critical thinking and creativity. During the 1990s, as sponsored by the Committee on Pre-College Philosophy of the American Philosophical Association (APA), an interdisciplinary group of 46 international experts from the fields of humanities, social sciences, and education met to reach a consensus on CT, which could support future research work.3 These experts produced a worldwide recognized report, titled Delphi Report, in which they established that "critical thinking is the purposeful, self-regulatory judgment that leads to interpretation, analysis, evaluation and inference, as well as the explanation of the evidential, conceptual, methodological, criteriological or contextual considerations on which judgment is based".3(p.2) According to Huang et al.,4 CT involves higher mental abilities, it is a prerequisite for effective judgment and the expansion of knowledge and is required in a healthcare professional who can be capable of accessing and interpreting information appropriately. With the aim of addressing the challenges of teaching and assessing the CT skills of health professionals, the "North American Millennium Conference on Critical Thinking" was organized. The conference enabled the development of strategies for inclusion in the principles of CT as well as the preparation of methods for assessing CT in the curricula of professions in the health field. The product of this conference culminated in a consensus that includes critical thinking as a core competence for nurses and emphasizes the teaching of this skill by professors.4 Two literature reviews on nursing education indicated the need to instruct nurses with CT skills has increased as a response to the rapid change in the health care environment.5–6 According to the authors, CT is needed not only in the clinical practice environment, but also required as a comprehensive component in Nursing education programs for the development of students' CT skills.5–6 Chang et al.7 claim that CT skills had a positive correlation to nurses' competence.7 Critical thinking is the focus of interest of professors and researchers around the world, with the need to educate critical and reflective practitioners in knowing how to act and making a difference in society becoming increasingly clear.1–23 Thus, this systematic literature review aims to evaluate the evidence available in the literature on the effectiveness of teaching strategies used for the development of CT among undergraduate nursing students. In a preliminary search in the Cochrane Database of Systematic Reviews, Joanna Briggs Institute Library of Systematic Reviews, PubMed, and PROSPERO, three systematic reviews were found,24,26,27 as well as a protocol for a systematic review related to the effectiveness of strategies for addressing CT in nursing students.25 Yuan, Willians and Fan24 conducted a systematic review to identify and gather available evidence on the development of CT among nursing students by using problem-based learning (PBL).24 Studies in English and Chinese, published within the period from 1990 to 2006, were included. 24 Evidence has shown that PBL did not promote the development of CT skills among undergraduate nursing students.24 Further, Tang and Sung25 prepared a protocol for systematic review in order to synthesize the best available evidence on the effectiveness of PBL to address CT with nursing students.25 For inclusion in the systematic review, the authors will at first consider experimental studies that used PBL as an intervention strategy for nursing students, and those that assessed CT skills as a result of studying through the means of the California Critical Thinking Disposition Inventory.25 Publications in English and Chinese will be selected.25 Kong et al.26 conducted a systematic review and meta-analysis to determine the effectiveness of PBL to indoctrinate CT among undergraduate nursing students as compared to the strategy of traditional lectures. Nine articles were included in the meta-analysis. Despite the moderate heterogeneity (I2= 45%), the result of the meta-analysis indicated that nursing students who underwent PBL, as compared to those who attended lectures, had significantly higher CT levels (SMD = 0.33; 95%IC= 0.13-0.52; p = 0.0009).26 The systematic review conducted by Chan sought to assess how CT is perceived and which strategies and obstacles are potentially involved in the teaching and learning process of CT among studies with a qualitative design, published between 2002 and 2011.27 Seventeen studies were selected from the databases, including The British Nursing Index, Ovid MedLine, CINAHL, PsycINFO, and Scopus.27 The results showed that the concept of CT has undergone several changes over time, and there remains a lack of explanation among teachers and students in the field.27 The teaching strategies for promoting CT frequently discussed were questioning and reflective writing.27 The authors identified a need to conduct a systematic review that assesses the effectiveness of new teaching strategies and interventions for improving the competence of educators to teach CT as well as for promoting CT development among nursing students. As mentioned earlier, studies included in previous systematic reviews on this topic have emphasized on teaching by PBL and have neglected other teaching strategies used in nursing education. This favors the study of only one type of teaching strategy and disfavors comparisons between any other types of existing strategies. Based on this, Chan27 also indicated the need for a systematic review of quantitative studies to be conducted, in order to identify the most effective teaching strategies for CT among nursing students that are currently available.27 Hence, the present systematic review will examine research that addresses this urgent and current need. Thus, the aim of this systematic review is to highlight the teaching strategies that promote CT in students of undergraduate courses in nursing.