Object-orientation is a language design and programming paradigm aiming at better structuring, reusing, and maintaining properties of software. This paradigm has been successfully combined with conventional programming languages, as well as with functional and logic programming languages; it seems obvious that object-orientation has come to stay. Recently, some suggestions to extend the attribute grammar formalism with features supporting object-orientation have been proposed. These proposals are reviewed, and the approach taken in the TOOLS system is described and motivated. It is demonstrated that object-orientation contributes to the uniformity and applicability of attribute grammar descriptions.