The Building Performance Ontology (BOP) aims to enable the integration of topological building information with static and dynamic properties, to create a homogeneous data environment used by complex building performance assessments. It helps building managers and their software to deal with the large heterogeneity of information. While the data describing static and dynamic properties is fundamentally different, they share a similar context with a complex spatio-temporal resolution. The goal of this ontology is to represent this complex contextual information similarly for different types of information, which will increase the opportunities for using the linked data in complex equations and improves machine-readability. We tried to be as semantically correct as possible, while also aiming for simple and intuitive queries. By (re-)using concepts from major ontologies in the field, BOP could easily be integrated with a wide range of existing ontologies and datasets.