This book constitutes the thoroughly refereed proceedings of the 15th International Conference on Collaborative Computing: Networking, Applications, and Worksharing, CollaborateCom 2019, held in London, UK, in August 2019. The 40 full papers, 8 short papers and 6 workshop presented were carefully reviewed and selected from 121 submissions. The papers reflect the conference sessions as follows: cloud, IoT and edge computing, collaborative IoT services and applications, artificial intelligence, software development, teleportation protocol and entanglement swapping, network based on the neural network, scheme based on blockchain and zero-knowledge proof in vehicle networking, software development.