The present narrative review explores the multifactorial aetiology of rheumatoid arthritis (RA) and other immunemediated inflammatory disorders (IMIDs), emphasising the significant role of various environmental factors in disease development and exacerbation. Key modifiable environmental factors such as cigarette smoking and air pollution are identified as major contributors to RA. We will also focus on the influence of weather, seasonality, and particularly vitamin D levels, on RA activity, suggesting potential for seasonal management and supplementation to mitigate disease severity. The emerging role of diet and the gut microbiome in RA pathogenesis and progression is discussed as well, with dietary interventions and specific nutrients like omega-3 fatty acids offering protective benefits against inflammation. Despite the mounting evidence around these factors, further research is needed, to better understand the clinical impacts on RA, including well-designed randomised clinical trials.