Sustainable aspects of buildings became one of the most crucial aspects of the built environment. The thermal performance can be improved through sustainable design guidelines and, thus, reduce energy consumption. This review covered studies that addressed Window Wall Ratio (WWR) and Window Orientation (WO) and their effect on thermal performance. WWR as a design variable that deals with window design, while the WO as an environmental variable that deals with orientation. The results will help to highlight open issues and research directions in the context of WWR, WO and integrations with other factors in buildings. Keywords: WWR, window design factors, Energy, WO eISSN: 2398-4287© 2020. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: