Effects of alkali-resistant glass fiber reinforcement on the flexural strength and ductility, restrained shrinkage cracking and temperature resistance of lightweight concrete were investigated. All these properties of lightweight concrete benefitted from the introduction of alkali-resistant glass fibers. Fiber mass fractions of 0.5–3.0%(volume fractions of 0.125–0.75%) were investigated; fiber mass fractions of 1.0–2.0%(volume fractions of 0.25–0.5%) were sufficient for control of restrained shrinkage cracks and enhancement of the flexural toughness and temperature resistance of lightweight concrete.