INTRODUCTION: The global uptake rates of lung cancer screening (LCS) with low-dose CT remain low. Since numerous factors contribute to the underuse of LCS, a theory-informed approach to identify and address the uptake of LCS barriers and facilitators is required. This study aims to document the methods which were used to identify, appraise, and synthesise the available qualitative, quantitative, and mixed methods evidence, addressing the barriers and facilitators at the individual and healthcare provider level, according to the social-ecological model, before identifying gaps to aid future practices and policies. METHODS AND ANALYSIS: The following databases will be searched: PubMed, Ovid (Journals @ Ovid Full Text and Ovid MEDLINE), EMBASE, CINAHL, PsycINFO, Cochrane Library, Chinese Biomedical Database, Chinese National Knowledge Infrastructure, and Wanfang database, from their creation up to 31 December 2020. Two reviewers will be involved in independently screening, reviewing, and synthesising the data; and calibration exercises will be conducted at each stage. Disagreements between the two reviewers will be resolved by arbitration by a third reviewer. The Critical Appraisal Checklist for Studies Reporting Prevalence Data from the Joanna Briggs Institute, the Critical Appraisal Skills Programme criteria adapted for qualitative studies, and the 16-item Quality Assessment Tool (QATSDD) will be used in the quality assessment of primary studies. We will perform data synthesis using the Review Manager software, V.5.3. ETHICS AND DISSEMINATION: This study is a review of published data and therefore needs no ethical approval. The findings of this systematic review will be published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: CRD42020162802.