Customizable meta-objects are a powerful abstraction for extending language features and implementation mechanisms, but interpretive execution suffers from severe performance penalty. Some of this penalty can be reduced by applying partial evaluation to metainterpreters, but partial evaluation of meta-objects in existing concurrent object-oriented languages is ineffective. This paper proposes a new meta-object design for our reflective language ABCL/R3. It yields metaobjects that can be optimized effectively using partial evaluation. The crux of the design is the separation of state-related operations from other operations, and this separation is accomplished by using reader/writer methods in our concurrent object-oriented language called Schematic. Our benchmark trials show that non-trivial programs with partially evaluated meta-objects run more than six times faster than ones that are interpreted by meta-objects. In addition, a partially evaluated program that uses a customized meta-...