Physical and mental illnesses are driven by ethnicity, social, environmental and economic determinants. Novel theoretical frameworks in rheumatoid arthritis (RA) focus on links and adverse interactions between and within biological and social factors. This review aimed to summarise associations between socioeconomic status (SES) and RA disease activity, and implications for future research. Articles studying the association between SES and RA disease activity were identified, from 1946 until March 2021. The research question was: Is there an association between social deprivation and disease activity in people with RA? Articles meeting inclusion criteria were examined by one author, with 10% screened at abstract and full paper stage by a second author. Disagreements were resolved with input from a third reviewer. Information was extracted on definition/measure of SES, ethnicity, education, employment, comorbidities, disease activity and presence/absence of association between SES and disease activity. Initially, 1750 articles were identified, with 30 articles ultimately included. SES definition varied markedly—10 articles used a formal scale and most used educational attainment as a proxy. Most studies controlled for lifestyle factors including smoking and body mass index, and comorbidities. Twenty-five articles concluded an association between SES and RA disease activity; two were unclear; three found no association. We have demonstrated the association between low SES and worse RA outcomes. There is a need for further research into the mechanisms underpinning this, including application of mixed-methods methodology and consideration of syndemic frameworks to understand bio–bio and bio–social interactions, to examine disease drivers and outcomes holistically.