Background: Psoriatic arthritis is an inflammatory arthritis associated with psoriasis. Patient education limits disability in rheumatic diseases and improves quality of life. Objective: To assess the patients’ knowledge about their disease in a sample of Iraqi patients with psoriatic arthritis and determine the relationship between sociodemographic, clinical characteristics and knowledge score. Methods: A sample of 100 adult Iraqi patients who met CASPAR criteria agreed to participate in this study over the period December 2021–July 2022. We reported the sociodemographic and clinical data, and after the participants completed the knowledge questionnaire, we ranked them into three categories: good, average, and bad. Results: There were 88 patients with good knowledge (88%), 12 (12%) with average knowledge, and no patient had bad knowledge. There were no significant statistical relationships between the mean total knowledge score and gender, age, marital status, smoking, occupation, educational level, and family history of psoriasis or psoriatic arthritis. There was a significant negative statistical relationship between the mean total knowledge score and the age at onset of arthritis. The mean total knowledge score did not exhibit any statistical relationships with the age at onset of skin disease, the duration of arthritis, the duration between skin disease and arthritis, or BMI. Conclusions: Iraqi patients with psoriatic arthritis have a good level of knowledge about their disease, despite inadequate awareness about specific aspects related to their disease. There was a significant negative relationship between the Iraqi PsA patients` knowledge and the age at onset of arthritis.