The Testing and Test Control Notation TTCN-3 is the only standardized test specification and implementation language used in industry and research to define and execute different types of tests in multiple domains like e.g. telecommunication or automotive. The notation supports an abstract description of test scenarios. Due to multiple tool support, including powerful open source projects, it is successfully worldwide in use e.g. for testing and certification of mobile phones by 3GPP or the oneM2M products. The presentation introduces the goals, technical concepts and various applications of the TTCN-3 technology.