Objectives: Patients' pain behavior plays an important role in the interaction between patients and their partners, as acknowledged in operant models of pain. However, despite the considerable research attention to pain behaviors, the underlying motives of such behaviors are still unclear. The current study explores the motives to engage in pain behaviors and the possible discrepancies between individuals experiencing pain and partners' perceptions of those motives. Methods: A qualitative study was performed, comprising semistructured interviews with 27 patients with chronic low back pain and their partners. They were recruited through purposive sampling at 2 pain clinics located in Tehran, Iran. Results: Patients and partners mentioned a variety of motives for pain behaviors, including protecting oneself against more pain, regulating negative emotions, informing others about the pain severity, seeking validation or intimacy, gaining advantages from pain, and expressing anger. Patients and partners revealed the most similarities in motives such as protecting oneself against more pain and informing others about the pain severity. However, partners rarely acknowledged patients' motives for seeking validation and they were more likely to mention negative motives (eg, expressing anger). Discussion: In conclusion, partners are more likely to attribute negative motives to the patient's pain behaviors, which may lead to their hostility toward patients. The findings of this study provide new insights into motives of pain behaviors from the perspective of patients and partners, which can inform couple-based interventions in terms of effective pain communication.