Six 1/2 scaled, single-storey, one-bay frame specimens were tested in this study to investigate the seismic behavior of masonry infilled reinforced concrete (RC) frames subjected to lateral loading. The parameters investigated include types of masonry and types of openings. The crack patterns, failure modes, load-displacement hysteretic loops, stiffness degradation, and energy dissipation capacity are presented and discussed. It is found that the infilled wall (with or without openings) could improve the behavior of RC frames significantly. Moreover, as expected, the infilled frame with higher strength masonry performed better than those with relatively low strength masonry. Furthermore, the openings may detriment the stability of the infilled walls. The concentric widow opening has worse effects than the eccentric door opening. The proposed analytical model could determine the load resisting capacity of bare frame and infilled frame with reasonable accuracy.