This book constitutes the proceedings of the third International Workshop on Symbiotic Interaction, Symbiotic 2014, held in Helsinki, Finland, in October 2014.The 8 full papers and 5 short papers presented in this volume were carefully reviewed and selected from 16 submissions. They are organized in topical sections named: definitions of symbiotic interaction; reviews of implicit interaction; example applications; experimenting with users; and demos and posters.