Studying the deformation and breakup behavior of molten metal droplets is crucial in the context of their atomization to form metal powders. During secondary breakup, droplets deform and then break up. The initial deformation plays an important role in the breakup phenomenon, as it is the first stage that the droplet goes through during its breakup. In this work, secondary breakup experiments were performed at low Weber numbers where the bag breakup mode is predominant and deformation characteristics of the droplet were measured. Since studies on molten metals are scarce, the test liquids included high-surface-tension liquids (molten tin and gallium), as well as water and ethanol, to obtain a wide range of surface tension values (0.71-0.022 N/m). The objectives were to investigate deformation and breakup behavior of molten metals compared to waterlike liquids, to examine the range of Weber numbers corresponding to the bag breakup mode and to check the applicability of the standard Taylor analogy breakup (TAB) model to molten metal atomization. The experimental results show that the deformation and breakup characteristics of molten metal droplets are different from classical waterlike liquids; the extent of deformation and the deformation rate are low for molten metals. To take this into account, a correlation relating the maximum cross-stream length to the initial droplet diameter is proposed. A semianalytical model which predicts the deformation of the droplet is also presented. The results from this model agree well with our experimental results and the literature. The model also performs better than the TAB model for most of the conditions studied. © 2019 by Begell House, Inc. www.begellhouse.com