A bend stiffener is operable to be installed on site in a collapsed state and expanded upon installation to provide increased coverage of a tubing string to be reinforced by the bend stiffener. The bend stiffener is expandable upon the tripping of tubing through the bend stiffener. The bend stiffener includes a flexible sleeve having an outer flange at an upper end and sized to receive the tubing. The bend stiffener also includes an intermediary sleeve and an external sleeve. The intermediary sleeve has a cylindrical body and an internal flange for engaging and supporting the outer flange of the flexible sleeve. Similarly, the external sleeve has an internal flange for supporting an external flange of the intermediary sleeve. When installed, the flexible sleeve slides from the intermediary sleeve and the intermediary sleeve slides from the external sleeve so that each sleeve encloses and reinforces a segment of tubing.