Improving the proficiency in mathematical literacy is one of the efforts to improve the human resources quality. Its development describes the students' strengths and weaknesses to support the improvement. The research tried to describe the development of students' proficiency in mathematical literacy, based on the school level and the students' gender. The research was a cross-sectional developmental study. The population was all of students ranging between 13 and 16 years old in the Province of Yogyakarta Special Region, Indonesia. In the sample were 1,001 students in the 8th, 9th and 10th grade, determined to use the combination of stratified and the cluster random sampling technique. The data were collected using 30 items. The data analysis was conducted by estimating students' ability through the item-response theory approach under the Rasch model and by using the parameters that had been adjusted to the international study item parameter under the concordance model for the linking score to interpret the students' development. The research results showed that there has been improvement of literacy proficiency among the 8th, 9th and 10th grade students. The development would generate higher scores utilizing multiple choice test items. There was a tendency that the school level, gender, the form of items, content, context, and process literacy would influence the mathematical literacy score. The efforts for improving proficiency in mathematical literacy were discussed.