Background Real-world data on the long-term use of guselkumab for treatment of psoriasis are still limited. Objective We aimed to evaluate long-term efficacy, safety, and drug survival of guselkumab in a real-world setting. Methods This is a retrospective study analyzing Czech Republic registry (BIOREP) data of patients treated with guselkumab. Results In total, 333 patients were included. Improvement in Psoriasis Area and Severity Index (PASI) score was significant. Mean PASI score decreased from 16 at baseline to 0.7, 0.9, and 0.8 after 12, 24, and 36 months, respectively. Absolute PASI scores of ≤ 3 and ≤ 1 were achieved in 93.9% and 77.9%, 94.2% and 71.0%, and 94.8% and 70.7% of patients after 12, 24, and 36 months, respectively. Response PASI 90 and PASI 100 were attained in 81.8% and 57.1%, 75.4% and 50.7%, and 75.9% and 55.2% of patients after 12, 24, and 36 months, respectively. The percentage of patients achieving PASI 90 and PASI 100 responses was higher throughout the study in bio-naive and in normal-weight patients, while presence of psoriatic arthritis had no influence. Improvement in Dermatology Life Quality Index (DLQI) score was also significant; mean DLQI score decreased from 14.2 at baseline to 0.9, 1.0, and 0.7 after 12, 24, and 36 months, respectively. Patients with PASI 100 had lower mean DLQI throughout the study compared with patients with PASI 90. Major reason for discontinuation was loss of effectiveness in 7.1% of patients, while only 0.6% were due to adverse events. Overall cumulative drug survival was high, with only a minimal decline over time, reaching 91.6%, 87.0%, and 85.5% after 12, 24, and 36 months, respectively. Drug survival was not affected by previous biological treatment, patient weight, or presence of psoriatic arthritis. Conclusions This real-world study demonstrated the long-term effectiveness, good safety profile, and high drug survival of guselkumab treatment over a period of 36 months.