The Revised Illness Perception Questionnaire (IPQ-R) has been shown to assess illness perception reproducibly in primary cutaneous T-cell lymphomas (CTCL). Illness perception reflects patients' individual concepts of understanding and interpretation of the disease, influencing illness behaviour and health-related quality of life (HRQOL). This study investigated the clinical relevance of the relationships between illness perception, illness behaviour, and HRQOL in CTCL and cutaneous B-cell lymphomas (CBCL). A total of 92 patients completed the IPQ-R, the Scale for the Assessment of Illness Behavior (SAIB), and a skin-specific HRQOL tool (Skindex-29). Data on illness behaviour were not evidently related to illness perception, whereas illness perception was significantly associated with HRQOL. Both, IPQ-R and HRQOL results correlated with disease entity, stage, and socio-demographics. Only IPQ-R results provided practical information on patients' needs to train personal coping strategies. IPQ-R assessment in CTCL and CBCL might be a useful instrument to improve individual disease management.