The study aims to examine the relationship between illness acceptance, psychological well-being, and anxiety in individuals with chronic diseases. Data were collected from 510 participants through face-to-face surveys. The data collection instruments included a personal information form, the Illness Acceptance Scale, the Anxiety Scale, and the Psychological Well-Being Scale. Analyses were conducted using SPSS 26 software. Since the data showed a normal distribution, parametric tests were employed. The majority of participants were female, under 45 years of age, had completed primary education, and were married. Circulatory system diseases were the most common, and most patients had been diagnosed for 13 years or longer. Significant differences were observed between the scales based on variables such as disease diagnosis and gender. A weak negative correlation was found between illness acceptance and psychological well-being, while a weak positive correlation was observed between illness acceptance and anxiety. The results highlight the complex and multidimensional nature of the relationship between illness acceptance, psychological well-being, and anxiety. They emphasize the importance of individuals’ adaptation to illness in this context, and indicate that factors such as disease stage, symptoms, and treatment should be considered to achieve clearer results.