Collaborative improvement is a purposeful inter-company interactive process that focuses on continuous incremental innovation aimed at enhancing the partnership's overall performance. Considering that in such an environment the capability to learn jointly and individually is crucial, this paper takes a learning perspective on collaborative improvement and addresses the question: How do organisational learning and collaboration interplay and affect improvement performance? Based on an analysis of three dyads of the same Extended Manufacturing Enterprise, this paper concludes that a robust learning environment (willing and able to learn) creates operational, relational and learning outcomes - a self-reinforcing process. A weak learning environment (some willingness but limited ability to learn) creates operational outcomes but is sensitive to 'accidents' and thus at risk of actually producing negative relational and learning outcomes. A 'blocked learning' environment (no willingness to learn) may create good operational outcomes, but will not produce learning and relational outcomes. Consequently, it is doubtful if such situations are sustainable.