The fit of a bra is critical, not only from a comfort and support perspective but it can significantly impact on the health and well-being of the wearer (Chan et al. 2001). Bra fitting is particularly important for adolescent females as it can affect the size, shape, and composition of their bones and breasts during this growth period (Strasburger 2006). Wood et al. (2008) found that 80% of young women, aged 18-26, that they investigated, wore the wrong sized bras. Bra fitting is still an inherently subjective process. It relies on the experience of a professional bra fitter to assess the fit against a checklist of fitting criteria. More accurate fitting could be achieved if the process was made more objective. This paper presents the results of a study to objectively measure the fit of crop-top bras. Crop top bras are currently very popular because they are highly extensible, body hugging garments that are comfortable to wear, imperceptible under clothing and protective. Furthermore they have no supporting wires to cause excessive skin pressure which may inhibit body growth (Ashby 2005). However a critical feature of these bras is that they can cause breast deformation which detracts from their other beneficial features. This study specifically addresses these effects of breast deformation and defines new, objectively measurable parameters to quantify it, through a series of wearer trials and the analysis of 3D body scans conducted for a range of commercial crop top bras and newly developed bras with increased cup volumes designed to reduce the effects of breast deformation.