Software engineering is becoming more and more mature as an academic discipline. Its fundamental concepts are better identified and defined and its underlying methods are better understood. Despite this, few software engineering theories have been proposed, and none of them have achieved significant recognition so far. GTSE 2013 aims at providing a forum for discussing the concept of a general theory in software engineering. The goal is to launch a scientific process of proposing, generating, criticizing and testing general theories of software engineering, and thereby, lead the software engineering discipline towards a more mature theoretical state.