This article presents results of an experimental study conducted to investigate the influence of fiber volume fraction, fiber type, and presence of fly ash on mechanical properties of fiber-reinforced, lightweight aggregate, cellular concrete (FRLACC). Steel fibers are added at V(f) of 0.5, 1.0, and 1.5%, and 25% of cement weight is replaced with fly ash in the control and FRLACC specimens that had shown the highest compressive strength in our preceding work. With the addition of 0.5% V(f) of fibers, the increase in compressive strength of the polypropylene FRLACC specimens is slightly higher than that of the steel FRLACC specimens, whereas decreases in their peak load and modulus of rupture over those of control specimens are observed. The findings of the experimental study also show that the utilization of 25% fly ash is more efficient in improving the mechanical properties of the steel FRLACC specimens than those of the polypropylene FRLACC specimens.