Green walls can be basically defined as climbing plants grown either directly against, or on support structures integrated to external building walls. Similar to other types of green infrastructure, they are in the centre of interest owing to their remarkable benefits such as reducing internal building temperatures, mitigating building energy consumption and facilitating urban adaptation to a warming climate. In this research, thermal regulation feature of green wall systems is experimentally and numerically investigated through a case study conducted in the Jubilee Campus of University of Nottingham. Internal wall temperatures are measured time-dependently for different cases and the results are compared with those of ordinary walls for a reliable and realistic approach. Different sky conditions are also considered within the sdope of this research as an independent variable. Experimental results are verified by numerical models carried out in Ecotect. The results reveal that an average of 2.5 degrees C reduction in internal wall temperature can be achieved via green walls with about 10 cm thick climbing vegetation of Hedera helix, which is very promising. (C) 2016 Elsevier Ltd. All rights reserved.