Background Systemic lupus erythematosus (SLE) is a complex autoimmune disease that can involve multiple organ systems. Exposure to ultraviolet radiation (UVR) can exacerbate pre-existing SLE, and can even induce systemic manifestations. This study aimed to investigate the photoprotective habits of children with SLE and the factors that significantly influence those photoprotective habits. Methods This questionnaire-based cross-sectional study included paediatric SLE patients being treated at the Department of Paediatrics at Siriraj Hospital, Mahidol University, between September 2018 and September 2019. Data were obtained from medical records and a face-to-face interview. Results Ninety-six patients were enrolled, with a female-to-male ratio of 8:1. The mean age of patients at enrollment was 13.7 ± 2.4 years. Of the 96 patients, 70 (72.9%) reported being directly exposed to sunlight for less than two hours per day, but 39% of patients spent time in the sun during the peak hours of UVR. Up to 95% of patients used sunscreen. However, only 64% of patients applied it every day, and only 35% of patients used an adequate amount of sunscreen. Girls were significantly more likely to apply sunscreen every day than boys were ( p = 0.041). SLE patients with a shorter disease duration had significantly greater exposure to sunlight than patients with a disease duration of more than four years ( p = 0.040). Conclusion Sunscreen was the most common photoprotective method. However, most patients used sunscreen inappropriately. A shorter disease duration was significantly associated with more sunlight exposure. Regular evaluation and emphasis of the importance of photoprotection should be encouraged among paediatric SLE.