In the process of implementation and innovation of paediatric dosage forms, buccal films for transmucosal administration of drug represent one of the most interesting approach. In fact, films are able to provide an extended duration of activity allowing minimal dosage and frequency and offer an exact and flexible dose, associated with ease of handling. The objective of the present study was to develop polymeric films for the sustained release of ondansetron hydrochloride, a selective inhibitor of 5-HT3 receptors indicated in paediatrics for the prevention and treatment of nausea and vomiting caused by cytotoxic chemotherapy or radiotherapy and postoperatively. Films were prepared by casting and drying of aqueous solutions containing different weight ratios of hydroxypropylmethylcellulose (HPMC) with chitosan (CH) or sodium hyaluronate (HA) or gelatin (GEL) and characterized for their physico-chemical and functional properties. The presence of HA, GEL and CH did not improve the mucoadhesive properties of HPMC film. The inclusion of GEL and CH in HPMC film increased in vitro drug release with respect to the inclusion of HA, although films containing HA showed the highest water uptake. Moreover in agreement with the release behaviour, the inclusion of CH and GEL provided higher drug permeation through porcine buccal mucosa with respect to HPMC film and ensured linear permeation profiles of drug.