Due to its biodegradablity and biocompatibility, gelatin is routinely used in hydrogels for biomedical applications such as drug delivery, tissue engineering, and 3D bioprinting. Gelatin-based hydrogels are synthesized by the crosslinking of functionalized gelatins. Depending on the identity of the functional groups, several different processes can be used to synthesize crosslinked gelatin hydrogels, including radical-based (either thermal or photochemical) and click chemistry methods. Azide-functionalized gelatin can be used in the synthesis of hydrogels using click chemistry with alkyne-containing substrates.