Developed to evaluate secondary school students' writing fluency skills, this study is descriptive in nature and uses a mixed method approach. During the research, the researcher attempted to identify students' abilities to write in terms of quantity and complexity, on the one hand, and also attempted to identify findings on accuracy, the organization of ideas, and the obstacles to fluent writing using qualitative data collection tools. The research population consisted of 379 secondary school students in the city center of Hatay, Turkey. Students were given 5 minutes to write, with most texts reaching between 91 and 125 syllabes. Students' texts scored 5 points, 19-36 points, and 3 points on the "Accuracy," "Syntactic Complexity," and "Organization of Ideas" dimensions, respectively. Students' lexical diversity was found to be 17.48% when taking polysemy into account, however, the lexical diversity ratios of the students are 20.9%. The lexical density percentage of students was found to be 86.01%.