A convertible shoe system includes a removable heel attachment configured to selectively transform the shoe between a high-heel configuration and a flat configuration. The shoe includes an attachment platform having an interlocking portion with a cylindrical opening and notches. The removable heel attachment includes a heel lock and a heel lock post with radially extending lock ears. The heel lock post is insertable into the cylindrical opening with the lock ears aligned with the notches, and rotation of the heel attachment moves the lock ears out of alignment to retain the heel lock post in the opening. When the removable stelo is present, a portion of the stelo is positioned between the heel lock and the attachment platform such that rotation of the heel attachment clamps the stelo between the heel lock and the attachment platform. Removal of the heel attachment converts the shoe to a flat configuration.