OneAPI is a cross-industry, open, standards-based unified programming model. The oneAPI specification extends existing developer programming models to enable a diverse set of hardware through language, a set of library APIs and a low-level hardware interface to support cross-architecture programming. It builds upon industry standards and provides an open, cross-platform developer stack to improve productivity and innovation. At the core of oneAPI is the DPC++ programming language, which builds on the ISO C++ and Khronos SYCL standards. DPC++ provides explicit parallel constructs and offload interfaces to support a broad range of accelerators. In addition to DPC++, oneAPI also provides libraries for compute- and data-intensive domains; e.g., deep learning, scientific computing, video analytics and media processing. Finally, a low-level hardware interface defines a set of capabilities and services to allow a language runtime system to effectively utilize a hardware accelerator.