ITU‐T's Technical Reports and Specifications 759 Overview of key performance indicators in smart sustainable cities Summary The Technical Specifications listed in section 2 give a general guidance to cities and provide an overview of key performance indicators (KPIs) in the context of smart sustainable cities. These Technical Specifications are expected to become an ITU‐T Recommendation. Keywords Cities, information communication technologies (ICTs), key performance indicators (KPIs), metrics and evaluation, smart sustainable cities (SSCs), sustainability impacts. Introduction According to the terms of reference (ToR) of the Focus Group on Smart Sustainable Cities (FG‐SSC), one of the objectives is to: Identify or develop a set of key performance indicators (KPIs) to assess how the use of ICTs has an impact on the environmental1 sustainability of cities. One of the specific tasks of FG‐SSC is to: Develop a document which contains a set of KPIs to assess the impact of the use of ICT projects in cities. These Technical Specifications are one of the deliverables developed by FG‐SSC which defines KPIs. The series of KPI definitions deliverables also include: Technical Specifications on key performance indicators (KPIs) related to the use of information and communication technology (ICT) in smart sustainable cities [ITU‐T L.KPIs‐ICT]. This document lists the KPIs focusing on ICT usage in SSCs. Technical Specifications on key performance indicators (KPIs) related to the sustainability impacts of information and communication technology (ICT) in smart sustainable cities [ITU‐T L.KPIs‐impact]. This document lists the KPIs proposed for ICT impact on sustainability. Technical Report on Supplement on key performance indicators (KPIs) for smart sustainable cities [ITU‐T L.KPIs‐Sup.]. This document provides information regarding KPIs and evaluation index systems of smart cities, KPIs of sustainable cities, etc. 1 The terms of reference for FG‐SSC particularly mentions environmental sustainability. However, this document tries to have a broader perspective and embraces also indicators that are related to quality of life, social and economic aspects.