Purpose To evaluate the psychometric properties of a Fall Concerns Scale for people who use Wheelchairs and Scooters (FCS-WC/S). Materials and methods Developed by fall prevention experts, FCS-WC/S underwent refinement through interdisciplinary reviews and focus groups with researchers, clinicians, and individuals who use WC/S full-time. The psychometric evaluation involved adults who used WC/S for ≥1 year and had ≥1 fall in the previous 3 years, recruited between April and September 2022. Results The FCS-WC/S evaluates fall concerns among people with various health conditions who use WC/S full-time across 33 daily activities. One hundred and twenty-four participants responded to the baseline survey. A subgroup of 63 people repeated the FCS-WC/S a week later. The FCS-WC/S demonstrated excellent internal and good test–retest reliability (α ≥ 0.90, ICC = 0.86–0.9), as well as concurrent validity (Spearman’s rho = 0.72) with the Spinal Cord Injury Falls Concern Scale (SCI-FCS). It effectively differentiated fear of falling levels from an established measure (ORs 4.1, 25.8, 46.7). Factor and parallel analysis revealed three factors, two of which were retained for further analysis. Conclusions Preliminary findings support FCS-WC/S validity and reliability for assessing fall concerns among individuals with various conditions who use WC/S. Further scale construction analysis is recommended.