The literature on the barriers encountered in the use of technology in education indicates that the internal barriers have a deterministic effect within this process. Therefore, it is important to determine the way teachers use technology as well as their opinions and attitudes towards technology in order to ensure effective use of technology in mathematics education. This study aims to determine the opinions and attitudes of secondary school mathematics teachers towards using technology in mathematics education. The convergent parallel design of a mixed methods study was used. The study included the participation of 57 teachers, who were determined on a voluntary basis using the convenience sampling method, from 22 different high schools in Turkey. A written opinion form and The Scale of Attitudes Towards Technology were used as data collection tools. The qualitative data obtained were analysed using descriptive and content analysis methods; quantitative data were analysed using multivariate analysis of variance. It was understood that the participants often used only smartboards in their lessons and they preferred teacher-centred classroom applications, which did not involve the hardware and software that allowed student interaction. It was found that the attitudes of mathematics teachers towards technology were “positive” which had a positive effect on using technology in lessons. It was observed that the attitudes of teachers towards technology did not change according to the training they received on using technology in lessons. It was concluded that the attitudes of teachers differed significantly across the scale or in various factors according to their age, the frequency of technology use in their lessons, the variety of hardware and software they use, and their opinions about the use of technology by the students. It can be argued that the positive attitudes of teachers towards technology had a positive effect on using technology in lessons.