Enterprise modelling aims at representing and describing organisations through the use of models. As organisations can be viewed from many perspectives, there now exists a plethora of different kinds of enterprise models. As a consequence, a perennial problem in the area has been how to integrate, relate and align models. This paper suggests that a value-aware approach can help to address this issue, and it outlines how the construction of enterprise models can be informed by taking the notion of value into account. The approach chosen is ontology-based. An initial ontology for value ascription is proposed, which is used for showing how common kinds of enterprise models can be adjusted to accommodate the notion of value. The proposed approach is expected to support integration, harmonization and documentation of models as well as traceability between models.