The gut microbiota plays a crucial role in the development and progression of autoimmune diseases by interacting with the host's immune system. This review summarizes the current understanding of the gut microbiota's role in autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren's syndrome (SS), type 1 diabetes mellitus (T1DM), ulcerative colitis (UC), and psoriasis. The gut microbiota influences immune homeostasis, modulates immune responses, and affects the balance between regulatory and pro-inflammatory immune cells. It also impacts the production of short-chain fatty acids (SCFAs), which have anti-inflammatory properties and help maintain the integrity of the intestinal barrier. The gut microbiota is involved in the regulation of innate and adaptive immunity, including the development and function of immune cells such as T cells, B cells, and innate lymphoid cells (ILCs). Dysbiosis of the gut microbiota has been linked to the onset and progression of autoimmune diseases, and interventions targeting the gut microbiota, such as probiotics, show promise as adjunctive therapies. The review highlights the importance of maintaining a balanced gut microbiota for immune health and suggests that further research is needed to fully understand the mechanisms underlying the gut microbiota's role in autoimmune diseases.The gut microbiota plays a crucial role in the development and progression of autoimmune diseases by interacting with the host's immune system. This review summarizes the current understanding of the gut microbiota's role in autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren's syndrome (SS), type 1 diabetes mellitus (T1DM), ulcerative colitis (UC), and psoriasis. The gut microbiota influences immune homeostasis, modulates immune responses, and affects the balance between regulatory and pro-inflammatory immune cells. It also impacts the production of short-chain fatty acids (SCFAs), which have anti-inflammatory properties and help maintain the integrity of the intestinal barrier. The gut microbiota is involved in the regulation of innate and adaptive immunity, including the development and function of immune cells such as T cells, B cells, and innate lymphoid cells (ILCs). Dysbiosis of the gut microbiota has been linked to the onset and progression of autoimmune diseases, and interventions targeting the gut microbiota, such as probiotics, show promise as adjunctive therapies. The review highlights the importance of maintaining a balanced gut microbiota for immune health and suggests that further research is needed to fully understand the mechanisms underlying the gut microbiota's role in autoimmune diseases.