Cities are facing multifaceted challenges of globalisation, climate change, economic and social changes. There is a growing literature on the need to develop green and sustainable cities to manage these urban challenges. How can the emerging information and communication technologies (ICT) be used to create more sustainable green cities? The paper will first discuss some of the key principles and practices of green and smart cities. It will then examine the potential and challenges of adapting a range of smart technologies for developing sustainable cities.