This book constitutes the refereed proceedings of the 12th International Conference on Software Process Improvement and Capability Determination, SPICE 2012, held in Palma de Mallorca, Spain, in May 2012. The 21 revised full papers presented and 14 short papers were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on organizational process improvement; SPI in small and very small enterprises; process models; SPI in automotive software and security; SPI in medical and safety critical systems; short papers.