IntroductionUnderstanding what enhances the motivation and performance of community health workers (CHWs) in humanitarian emergencies represents a key research gap within the field of human resources for health. This paper presents the research protocol for the Performance ImprovEment of CHWs in Emergency Settings (PIECES) research programme. Enhancing Learning and Research in Humanitarian Action (ELRHA) funded the development of this protocol as part of their Health in Humanitarian Crises (R2HC) call (No.19839). PIECES aims to understand what factors improve the performance of CHWs in level III humanitarian emergencies.Methods and analysisThe suggested protocol uses a realist evaluation with multiple cases across the 3 country sites: Turkey, Iraq and Lebanon. Working with International Medical Corps (IMC), an initial programme theory was elicited through literature and document reviews, semistructured interviews and focus groups with IMC programme managers and CHWs. Based on this initial theory, this protocol proposes a combination of semistructured interviews, life histories and critical incident narratives, surveys and latent variable modelling of key constructs to explain how contextual factors work to trigger mechanisms for specific outcomes relating to IMC's 300+ CHWs' performance. Participants will also include programme staff, CHWs and programme beneficiaries. Realist approaches will be used to better understand ‘what works, for whom and under what conditions’ for improving CHW performance within humanitarian contexts.Ethics and disseminationTrinity College Dublin's Health Policy and Management/Centre for Global Health Research Ethics Committee gave ethical approval for the protocol development phase. For the full research project, additional ethical approval will be sought from: Université St. Joseph (Lebanon), the Ethics Committee of the Ministry of Health in Baghdad (Iraq) and the Middle East Technical University (Turkey). Dissemination activities will involve a mixture of research feedback, policy briefs, guidelines and recommendations, as well as open source academic articles.