This report covers the activities and the performance of the Technology Executive Committee (TEC) and the Climate Technology Centre and Network (CTCN) in 2017. It includes one joint chapter and two separate chapters, one for each of the two bodies. The chapter of the TEC outlines the work undertaken by the TEC in 2017, covers its 14th and 15th meetings and includes its key messages for the Conference of the Parties (COP) at its twenty-third session. The chapter of the CTCN describes its work in 2017, covers the 9th and 10th meetings of the Advisory Board of the CTCN and contains key messages for COP 23. It also includes information provided by the United Nations Environment Programme on matters regarding its role as the host of the Climate Technology Centre. Annex I contains the procedures for preparing the joint annual report of the TEC and the CTCN to the COP. Annex II contains the inputs of the TEC to the assessment of the technical examination process on mitigation, pursuant to decision 1/CP.21, paragraph 113.