Background:Rheumatoid arthritis (RA) is an autoimmune disease characterised by swollen and painful joints. It is hypothesised that changes in lifestyle factors such as consuming a healthier diet may reduce the severity of RA symptoms. People living with RA commonly make alterations to their dietary intake with the hope of improving their symptoms. This systematic review aims to discuss the effects of dietary interventions with and without omega-3 supplementation for the management of rheumatoid arthritis.Methods:A systematic review of randomised controlled trials (RCTs) and non-randomised controlled trials (NRCTs) will be conducted. MEDLINE, EMBASE, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Methodology Register) and CINAHL will be searched from inception without using date restrictions. Primary outcomes will include measures of disease activity, inflammation and quality of life among adults living with RA. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the methodological appraisal of the studies will be assessed independently by two different reviewers (TR and AG) using the Cochrane Risk-of-Bias Tool for RCTs, and Risk-of-Bias In Non-Randomised Studies Tool for NRCTs.Ethics and dissemination:Ethical approval is not required for this systematic review. Only publically available data from previously published studies will be used. The findings of this systematic review will be submitted for publication in a peer-reviewed journal and presented at relevant conferences.PROSPERO registration:CRD42020147415(11/02/2020).