||The Business Process Model and Notation (BPMN) is a widely-used standard for business process modeling. However, major drawbacks are the limited support for organizational modeling and the only implicit expression of modalities through the structure of the process flow. In addition, the syntactical definitions of the BPMN specification are in several cases inaccurate, incomplete, or inconsistent. This doctoral dissertation addresses the identified issues and provides a formal definition of the BPMN syntax within an ontology (called the BPMN 2.0 Ontology) as well as an extension of BPMN with deontic concepts to highlight modalities and support actor modeling. The extension of BPMN with deontic concepts such as obligations and permissions is called Deontic BPMN and supported by a globally deterministic graph transformation based on the algebraic approach.