The aim of the research is to derive a framework for the evaluation of Computer Aided Software Engineering (CASE) tool learnability in educational environments. Drawing from the literature of Human Computer Interaction and educational research, a framework for evaluating CASE tool learnability in educational environments is derived. The two main differences between this framework and existing evaluation frameworks is that 1) it is specific to educational environments and 2) it recognizes the significance of contextual factors such as learning environment and teaching and learning methodologies in evaluating learnability. The framework is oriented towards learnability and is customisable. It helps to define the important issues related to CASE tool learnability, and allows conclusions to be drawn about all influential factors on learning in the given context. A detailed case study describes the application of the framework to evaluate the learnability of Rational Rose, a CASE tool used in an undergraduate Systems Analysis and Design course. (Contains 2 figures and 14 tables.)