The pain experience is impacted by physical, psychological, and social factors (Asmundson & Wright, 2004). Symptoms of anxiety and related disorders have been associated with varied pain syndromes, particularly chronic pain (i.e., pain lasting longer than 3 months [International Association for the Study of Pain, 1994]; Asmundson, Norton, & Vlaeyen, 2004a). Chronic pain models implicate pain-related fear and anxiety as leading to activity avoidance, impeded healing, and prolonged pain (Asmundson et al., 2004a; Vlaeyen & Linton, 2000). Indeed, researchers have focused on pain-related fear and anxiety, and anxiety sensitivity (AS) as key risk factors for chronic pain (Carleton & Asmundson, 2012). Contemporary research and theory has underscored intolerance of uncertainty (IU) as a key construct underlying anxiety and AS (Carleton, 2012; Hong & Cheung, 2015), implying a possible relationship with chronic pain (Carleton & Asmundson, 2012); nevertheless, little research has explored the role of IU in pain experiences. The present study examined IU and chronic pain experiences. Online participants (n = 470) with chronic lower back pain (CLBP) or no history of chronic pain completed self-report measures of pain-related constructs online, as well as a behavioural task to assess response to risk and uncertainty. Participants’ responses on the behavioural task and self-report measures were compared to evaluate between-group differences based on the presence of CLBP. The degree of uncertainty participants report about their pain was considered as well. IU was associated with pain characteristics, such that participants with CLBP exhibited higher IU. Risk-taking behaviour did not differ between groups. The risk task used may have an ecological validity limitation with respect to pain. IU contributed unique variance to reported pain. Significant positive correlations among IU, pain, AS, and pain-related anxiety were identified. The results have implications for understanding chronic pain, and for treatment research to explore whether mitigating uncertainty or IU may reduce pain and pain-related anxiety.