Purpose: The purpose of this paper is to contribute to the research methodology of analyzing learning in inter-organizational networks based on an object-oriented approach. Design/methodology/approach: The paper draws from the cultural-historical activity theory (CHAT), specifically from the concepts of the object of activity, developmental contradiction, and expansive learning. An intermediate concept, the "learning event," is elaborated to study in a longitudinal way collaboration in a small-firm network. Findings: Learning in inter-organizational networks is best captured by analyzing historically the expansive object-creation at multiple levels of activity. Learning takes place in a dialectical movement across the levels of collaboration and across the objects and outcomes created. Transitions across the levels are critical for learning apparently enhanced by a network's innovative capacity to create intermediate levels. This vertical dimension of collaboration alongside the horizontal dimension may enrich the CHAT approach. Research limitations/implications: The model of learning across levels is a generalization to be applied to analyses of learning in networks. The levels are historically emergent and are to be contextually explored case by case. Practical implications: Network partners are encouraged to analyze and utilize the learning potential of network activity where models are needed as pedagogic and developmental tools. Originality/value: The paper introduces a novel way of conceiving the levels of learning, and strengthens the focus on the object of activity accompanied by contradictions and tensions energizing collaboration and learning, which are often omitted in inter-organizational studies. (Contains 3 figures and 2 tables.)