An effective option to provide more affordable housing and promote urban density growth is increasing the allowable number of floors in residential light wood frame buildings from four floors to six floors. However, more supporting evidence is needed to demonstrate that this type of construction meets building code performance requirements. The study presents an overview of the research conducted at the University of Alberta to evaluate the thermal resistance performance of some of the potential energy efficient wall systems for mid-rise wood frame buildings. Firstly, some potential wall systems are selected for investigation based on a number of considerations, such as current practice, preliminary structural analysis, and expected energy performance. After preliminary structural analysis of the selected wall systems, they are manufactured and employed for field testing. Several sensors such as heat flux sensors, thermocouples and humidity sensors are installed on the wall systems for long term monitoring of the energy efficiency of the wall systems in severe weather conditions of Alberta. The proposed wall systems have also been tested in the laboratory for their structural capacities. This paper presents the thermal resistance and structural capacity test results of three types of wall systems that may be suitable for mid-rise wood frame structures: (i) 2”x6” (38 mm x 140 mm) staggered with12” (304.8 mm) spacing, (ii) 2”x6” (38 mm x 140 mm) staggered with 8” (203.2 mm) spacing, and (iii) 2”x8” (38 mm x 184 mm) conventional with 12” (304.8 mm) spacing.