Body temperature (T_b) is one of the most influential factors affecting physiological processes in ectothermic animals. Reptiles use behaviours such as shuttling, and postural and orientation adjustments to ensure that T_b remains close to a target. It is thought that target body temperature (T_target) is aligned to the physiological and behavioural thermal optima of the animal. The Sungazer (Smaug giganteus), a Threatened lizard species, is unique amongst the Cordylidae in that lizards inhabit self-excavated burrows in open grasslands, a habitat in which there are few exposed rock basking sites. In this situation, T_bs are likely to be greatly influenced by postural and orientation adjustments during basking. We measured T_bs using modified iButtons, and calculated T_target of free-ranging Sungazers in order to assess the impact of body posture and orientation in the thermoregulation of the species. We used camera traps to record lizard behaviour at burrow entrances and aligned these measures to measures of T_b. T_target was 30 ± 1.4 °C, and T_bs remained within this range for 371 ± 162 min per day. The anterior body-up postures resulted in faster heating and higher T_bs. Lizards heated faster when facing away from the sun and spent proportionally more time in this orientation in the morning when T_bs were lower than T_target. Our findings suggest that their wide behavioural repertoire allows Sungazers to thermoregulate effectively over a broad range of environmental conditions and may thus be able to effectively respond to changing climatic conditions.