It has been assumed that the use of lightweight aggregate concrete structures can largely reduce dead loads and thus reduces the earthquake effects without increasing the total cost. However, one of the primary concerns for these structures has been the plastic deformation capacity, ductility, and energy dissipation capacity. Tests were conducted for seismic performance of reinforced lightweight aggregate concrete (RLAC) frames that consisted of beams and columns of different cross-sections. Quasi-static reversed cyclic loads were performed on 1:2 scale RLAC model frames that had special cross-sections. It was demonstrated that the RLAC frames had inherent defects regarding seismic performance. This, however, did not have substantial influence on the integral seismic performance of the structures. It was concluded that the RLAC frames met normal service requirement with sufficient strength reservation. The RLAC frames may represent a viable alternative for ordinary reinforced concrete framed structures in low- to medium-rise buildings in frequent-occurring earthquake areas.