An ontology in computer and information science formally represents domain-specific knowledge, enabling structured data integration and interoperability. In tourism, ontologies are crucial for standardizing diverse data from sources such as travel agencies, airlines, and user-generated platforms, improving semantic search, personalized recommendations, and developing intelligent systems. This paper presents a comprehensive tourism ontology built on the tourism value chain, identifying key classes, their relationships, and integrating existing ontologies. The resulting hierarchical structure supports enhanced data analysis and system intelligence. Additionally, we provide guidance on how to use and contribute to the ontology, making it accessible for broader application and development.