This book constitutes the thoroughly refereed post-conference proceedings of the 12th International Joint Conference on Software Technologies, ICSOFT 2017, held in Madrid, Spain, in July 2017. The 17 revised full papers and 24 short papers presented were carefully reviewed and selected from 85 submissions. The topics covered in the papers include: software quality and metrics; software testing and maintenance; development methods and models; systems security; dynamic software updates; systems integration; business process modelling; intelligent problem solving; multi-agent systems; and solutions involving big data, the Internet of Things and business intelligence.