This book constitutes the refereed proceedings of the
12th International Colloquium on Theoretical Aspects of Computing, ICTAC 2015,
held in Cali, Colombia, in October 2015.

The 25 revised full papers presented together
with 7 invited talks, 3 tool papers, and 2 short papers were carefully reviewed
and selected from 93 submissions. The papers cover various topics such as
algebra and category theory; automata and formal languages; concurrency;
constraints, logic and semantic; software architecture and component-based
design; and verification.