Objective: To identify physical activity barrier prevalence and severity among manual wheelchair users (MWCUs) and test whether barrier impact is associated with self-reported physical activity level (PAL). Design: Cross-sectional survey. The Barriers to Physical Activity Questionnaire for People with Mobility Impairments (BPAQ-MI) was translated from English to Danish and administered online. The BPAQ-MI includes barriers within 4 domains and 8 subdomains and queries if an item hindered physical activity participation in the last 3 months (yes/no). If “yes,” participants graded barrier severity from very small (1) to very big (5). Barrier impact scores were summed within and across domains. Setting: General community. Participants: Danish MWCUs (N=181; 52.5% female, mean age, 48±14y.). Interventions: Not applicable. Main Outcome Measures: PAL was rated from not active (1) to extremely active (10). Individual barrier prevalence (frequency, %) and severity (median [interquartile range]) was computed. Unadjusted (Spearman rank correlations, domains, subdomains) and adjusted (multivariate linear regression, subdomains) associations between PAL and barrier impact were computed. Results: The 5 most prevalent barriers were reported by ≥49.6% of participants (2 intrapersonal and 3 community). The 5 most severe barriers all had a median of 5 (1 organizational and 4 community). Unadjusted analysis showed that PAL was inversely associated with total intrapersonal (r=−0.487, P<.01) and overall (r=−0.241, P<.01) impact and the intrapersonal “health” (r=−0.477, P<.01) and “beliefs/attitudes”(r=−0.307, P<.01) subdomains. Adjustment for shared variance revealed only the “health” subdomain impact score was independently associated with PAL (P<.001). Conclusions: Intrapersonal barriers were highly prevalent. Health-related barriers were inversely related to PAL. When organizational and community barriers were present, they were rated as particularly severe. These results provide novel information that can guide the design of future interventions aiming to increase MWCUs PALs.