An experimental and analytical study is carried out to investigate the effects of lateral loading type on the behavior of masonry infilled steel frames. During earthquake the lateral load is applied as distributed loading to the top beams and columns through rigid floors; however, in most available experimental studies the lateral loading is applied as concentrated loading. In this study, two identical specimens are tested and their behavior is compared under distributed and concentrated lateral loadings. Finite element models of the specimens are also developed and validated against the experimental results. To have a better view, the influence of loading type is studied on another experimental specimen having concentrated loading. A parametric study is also conducted on the influence of loading type in multi-span frames and infills with different aspect ratios. The obtained experimental results show that the distributed loading results in 18.5 and 29% increase in the strength and stiffness of Infilled frames, compared to the case with concentrated loading. Less strength and stiffness in specimens subjected to concentrated loading is a result of stress concentration at the infill corner near the loading point which leads to premature corner crushing. Therefore, it is believed that the codes’ formulas, mostly based on specimens with concentrated loading, are conservative, underestimating the real ultimate strength and stiffness of masonry infilled steel frames.