As the population ages, more individuals with autoimmune diseases are experiencing reproductive senescence. Understanding the impact of menopause and age-related androgen decline on disease onset and course, as well as the potential for hormonal interventions, is critically important. In men, lupus erythematosis (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS) are associated with lower androgen levels. However, the impact of age-related declines in testosterone, as well as of testosterone replacement, on disease course remains underexplored. In women, the course of all three diseases with onset after the age of menopause differs from that with onset before menopause. Early age at menopause is associated with increased disease risk, and after menopause, disease course changes in SLE and RA. Less is known about MS. This article summarizes what is known about the relationship between reproductive aging and autoimmune diseases in men and women, and highlights areas for further investigation.