Applying 3D printing in construction is a promising, sustainable alternative to conventional methods. However, the thermal and energy performance of 3D-printed structures remains underexplored, particularly regarding the interactions between geometric design, material selection, and printing parameters. This review addresses this gap by critically examining how main steps related to printing process impact on the thermal efficiency of 3D-printed buildings. Key findings indicate that material development needs to focus on mixes that balance thermal properties,printability,and structural integrity. The review demonstrates how optimising wall cross-sections and cavity shapes can reduce thermal conductivity and enhance energy efficiency. Innovative geometric designs, such as cellular and honeycomb structures, have shown improvements in thermal insulation. Optimising printing parameters such as extrusion rate and nozzle travel speed is crucial to minimise thermal bridges and reduce material anisotropy. Advanced numerical models, validated with experimental data and incorporating inhomogeneous porosity, anisotropy, and surface roughness, are essential for accurately predicting the thermal behaviour of 3D-printed structures. The review underscores the need for large-scale, long-term performance studies of 3D-printed structures under diverse climatic conditions. Additionally, developing standardised fabrication protocols and testing methods is essential to ensure consistent quality and broader adoption. Addressing these research gaps is crucial to fully realise the potential of 3D printing in sustainable construction and accelerate the adoption of additive manufacturing in the construction area.