The aim of this study was to examine prospective social studies teachers' efficacy perceptions of 21st century skills based on gender, grade, academic success and mastery of information-communication technologies. Descriptive survey model was adopted in the study. The sample of the study consisted of a total of 257 prospective social studies teachers, 175 females and 82 males, from two different state universities in Türkiye. The participation was on a voluntary basis. The findings revealed that the participants had a high level of 21st century skills perceptions. It was also found that the participants' efficacy perceptions of 21st century skills differed significantly by gender in favor of female participants in the total scale and life and career skills sub-dimension. However, there was no significant difference in the sub-dimensions of learning and regeneration skills and information, media and technology skills in terms of gender. In addition, it was found that the participants' efficacy perceptions of 21st century skills and sub-dimensions differed significantly in favor of those thinking that they had mastery of information and communication technologies in the total scale and in the sub-dimensions of life and career skills and information, media and technology skills. However, no significant difference was found in learning and regeneration skills sub-dimension in terms of mastery of information and communication technologies. Finally, it was found that the participants' 21st century skills perceptions did not differ by grade and academic success. [For the full proceedings, see ED630948.]