Introduction: Although respiratory physiotherapy techniques may reduce respiratory load in newborns, manual contact with the ribcage may interfere with pulmonary mechanics. Therefore, this systematic review aims to evaluate the effects of conventional and non-conventional respiratory physiotherapies on pulmonary mechanics of newborns., Methods and Analysis: We will search PubMed, LILACS, SciELO, ScienceDirect, Cochrane Central and Web of Science databases. Searches will be conducted from September 2022. We will include randomised clinical trials reporting thoracoabdominal synchrony, lung volumes and capacities, respiratory discomfort and pain in newborns aged between 1 hour and 28 days and admitted to neonatal intensive care units. We will exclude studies not fully available or incomplete and studies conducted with newborns presenting structural alterations. Two independent researchers will perform the study selection, data extraction and quality assessment. After consensus, one reviewer will proceed with the process. We will include studies published in English or Portuguese, without publication date restriction. An overview of the included studies and extracted information will be reported and the quality of studies will be assessed. A meta-analysis will be conducted if data regarding between-group comparisons are available., Ethics and Dissemination: Ethics approval is not required for this systematic review. Results will be presented in journals and national and international conferences, and findings will be shared on social media using accessible language., Prospero Registration Number: CRD42021266729., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)