The influence of temperature on the expansive behavior and microstructural damage of concrete due to the alkali-silica reaction (ASR) is studied experimentally by applying a new testing protocol, the Alkali-Wrapped Concrete Prism Test (AW-CPT). Early-stage expansion is highly dependent on temperature, more so than expansion in later stages. In the early stages of expansion, the ASR gel is well restrained so that the early-stage expansion rate mainly depends on reaction kinetics. In later stages, since the viscosity of the ASR gel is lower at higher temperatures, it flows out of the concrete prism through small cracks or pores, resulting in reduced paste cracking and an increased silica content detected in the wrapping cloth at higher temperatures. Consequently, the late-stage expansion rate is found to be reduced at higher temperatures. Therefore, greatly accelerated test conditions may lead to reduced expansion of the concrete prism during the AW-CPT.