This study proposes an analysis of the multiphysical phenomena and mechanisms governing the thermo-mechanical behaviour of energy piles. The analysis is based on the results of a series of full-scale in-situ tests, laboratory experiments and numerical analyses. First, the thermo-mechanical behaviour of energy piles is considered. Attention is given to both single and groups of energy piles. Next, the response of soils and concrete-soil interfaces subjected to temperature changes is reviewed. The behaviours of clayey soils in different overconsolidation states as well as of both concrete-sand and concrete-clay interfaces are analysed. Finally, aspects considered of paramount importance for the analysis and design (e.g., geotechnical, structural and energy) of energy piles are presented. Both floating and end-bearing energy piles are investigated. The goal of this paper is to increase the confidence of civil engineers on the performance of energy piles.