Wheelchair outcomes measures are useful to support evidence-based practice in wheelchair provision, especially in low- and middle-income countries (LMIC). The Wheelchair Interface Questionnaire (WIQ) was developed to provide a professional perspective on the quality of the interface between a wheelchair and its user. Studies conducted during the development of the WIQ indicated it has face validity and content validity. The objective of this field study was to conduct a subsequent investigation of the inter-rater reliability of the WIQ at a school for children with disabilities in Kenya. Eight practitioners with wheelchair experience from disparate cultural backgrounds participated in the study. They evaluated eight wheelchairs and the interface with their users. The interclass correlation coefficient (ICC) of the mean rating for the eight-item dataset was computed using SPSS. The ICC was found to be 0.911, indicating that the WIQ possesses inter-rater reliability. Common comment topics indicated that the qualitative data yielded by the WIQ is meaningful. Informal timing indicated that the WIQ is a brief measure. The WIQ is a reliable tool that can meet the need for a professional assessment of the wheelchair-user interface. The reliability of this questionnaire is important because the tool can be used to evaluate the interface between a wheelchair user and their wheelchair, strengthening evidence-based practice in wheelchair provision. Implications for Rehabilitation Based on the score of a specific wheelchair interface, a rehabilitation professional could recommend more assessment, seating modification, or wheelchair replacement in order to maximize rehabilitation benefit for a client The WIQ could provide evidence-based information to support the need for wheelchair repair or replacement to funders. In large-scale studies involving many of the same wheelchair type in the same setting, the WIQ could be used to identify problems with the interface between that wheelchair type and its intended user population so that manufacturers can make responsive design changes. The WIQ could be used in a clinical setting over time to identify the most common wheelchair interface issues for that setting.