The four-volume set LNCS 9296-9299 constitutes the refereed proceedings of the 15th IFIP TC13 International Conference on Human-Computer Interaction, INTERACT 2015, held in Bamberg, Germany, in September 2015. The 47 papers included in the second volume are organized in topical sections on computer-supported cooperative work and social computing; end-user development; evaluation methods / usability evaluation; eye tracking; gesture interaction; HCI and security; HCI for developing regions and social development; HCI for education.