Knowledge-based enterprises are typically conducting a large number of research and development projects simultaneously. This is a particularly challenging task in complex and diverse project landscapes. Project portfolio management (PPM) can be a viable framework for knowledge and innovation management in such landscapes. A standardised process with defined functions such as project data repository, project assessment, selection, reporting and portfolio re-evaluation can serve as a starting point. In this work, we discuss the benefits that a multidimensional evaluation framework can provide for knowledge-based enterprises. Furthermore, we describe knowledge and learning strategy and process in the context of PPM and evaluate their practical applicability at different stages of the PPM process.