Body image is defined as the thoughts, feelings, and perceptions a person has about their body. Body image disturbance is an increasingly important public health issue due to its documented associations with maladaptive health behaviors and diminished health outcomes. Emerging scholarship suggests focusing on body functionality (i.e., what the body can do) over appearance (i.e., how the body looks) may promote positive body image outcomes among women. However, this research is underdeveloped in considering the perspectives of women with disabilities, who experience profound health disparities and may be at heightened risk for body image disturbance due to differences in appearance and body function. To address this gap, I used a multi-phase, mixed-method approach to explore and measure aspects of body functionality as a component of body image among women with and without disabilities. In Phase I, women with visible physical disabilities (N = 15) participated in semi-structured interviews about body image and body functionality, aligned with a constructivist grounded theory approach. Phase I findings revealed a new construct, functional-aesthetic body image (FABI), and data were used to generate items for a FABI measurement scale. In Phase II, subject matter experts (SMEs; N = 6) reviewed the face validity of scale items. Items were revised in accordance with SME feedback. Community women with (n = 18) and without (n = 15) disabilities reviewed items for content consensus via a Delphi approach, demonstrating proof-of-concept for an application of universal design in measurement research. In Phase III, the scale was pilot tested with a national sample of women with and without disabilities (N = 285). Exploratory factor analysis revealed 22 items loading on a four-factor structure. Item analyses, bivariate correlations, and hierarchical regression models were computed to assess the scale’s internal consistency and convergent, discriminant, and incremental validity. The FABI scale was ultimately found to be a psychometrically sound and valid instrument for measuring functional-aesthetic body image among women with and without disabilities. This research makes novel contributions to the fields of body image and disability by illuminating new relationships between appearance and body functionality constructs. It also provides a methodological framework, Universal Design for Measurement, to support the inclusion and centering of people with disabilities within mainstream health and measurement research.