Expanded glass (EG) made from recycled glass waste was used as an aggregate in the production of engineered cementitious composites (ECCs) to improve their thermal conductivity. The corresponding influence of the EG content on the physical, mechanical, and durability properties was evaluated. The EG was used as up to 100% replacement of the conventional silica sand (SS) in ECCs. The physical properties evaluated are thermal conductivity and density, while the mechanical properties evaluated are the compressive, flexural, and tensile strengths alongside the permeability properties and drying shrinkage. The findings from this study showed that the use of EG as a replacement for SS as aggregate in ECCs resulted in an improvement in the thermal insulation properties and a reduction in density. The 28-day thermal conductivity of ECCs made with EG as 100% replacement of SS is 53.8% lower than that of the ECCs made with only SS as the aggregate.