The purpose of the study was to investigate teachers’ use of open-ended questions in classrooms. The study was conducted by using a mixed-methods design. The quantitative and qualitative parts of the study were carried out with 212 teachers and 65 teachers, respectively. A scaling form developed by using the rank-order scaling method was employed to collect the quantitative data. The scaling form helped to determine important factors to design open-ended questions for teachers. The qualitative data were collected by an open-ended question form and analyzed with the content analysis technique. While open-ended questions related to teaching objective(s) were identified as the most important factor, identifying time limit and point value was determined as the least important factor in the preparation of open-ended questions for teachers. The qualitative data results of the study revealed that teachers’ designing of open-ended question tasks related to learning goals specifically focusing on students’ higher-order skills was essential. Conversely, most of the teachers felt that they have difficulties with their use of open-ended questions/tasks. This suggested that providing professional development for both preservice and inservice teachers would be useful for developing and assessing open-ended questions/tasks effectively in classrooms.