Objective The aim of this study was to determine the effect of web-based education and counselling for patients with systemic lupus erythematosus on self-efficacy, fatigue and assessment of care. Methods The study was conducted as a randomized controlled trial. The study sample consisted of 80 patients divided into two groups: the experimental group ( n = 40) and a control group ( n = 40). Randomization was performed by simple random sampling. At the beginning of the study (month 0), data-collection forms were administered to both groups. Web-based education was carried out for the first three months, and counselling and information updates were given for the next three months for the experimental group. In the intervention process, the control group just received standard care. After six months, data-collection forms were administered to both groups again. Results The mean age of the participants in the experimental and control groups was 35.58 ± 8.40 years and 39.00 ± 12.71 years, respectively. In both groups, 95% of patients were women. Wilcoxon’s test was used for within-group comparisons before and after the study. The Mann–Whitney U-test was used to evaluate the difference between the two groups before the intervention and between the two groups after the intervention. We found that there was a significant improvement in fatigue, self-efficacy and assessment of chronic illness care in the experimental group at the end of the study ( p < 0.05). Conclusions The intervention had a positive effect on self-efficacy, fatigue and satisfaction with chronic illness. In accordance with the results, similar studies should be conducted for different patient groups in order to strengthen the results.