This study proposes evaluation dimensions of object-oriented systems modelling tools and activities available in object-oriented systems development practices. The dimensions ale developed based on previous research in cognitive psychology, information systems modeling study, and object-oriented systems analysis arid design areas. The proposed dimension is composed of two dimensions. The one dimension includes abstraction levels of modelling and the other includes process and representation in modeling activities. Experts on object-oriented modeling were selected to evaluate the practical validity of the proposed dimensions and applications of major object-oriented modeling tools during systems development project. Most of the tools were observed to be used for representing objects rather than for modeling the process of related objects. The proposed modeling dimension will be evaluated for acquiring general validity in future empirical research.