The objective of this study is to determine the ways in-service teachers in Turkiye make use of open educational resources and their opinions on using them. For this purpose, the explanatory sequential design has been employed. 588 teachers have participated in the quantitative part of the study; and ten have participated in the qualitative part on a voluntary basis. Data collection instruments have been (a) a personal information form developed by the researchers comprised of 16 questions and (b) a semi-structured interview form with 3 questions. The personal information form has been administered online to participants via social media. Whereas the interviews have been conducted using Zoom teleconferencing software. According to the findings, more than half of the teachers are knowledgeable on the matter of open educational resources and information resources consist of social media. It has been determined that female teachers make greater use of open educational resources than males. It has been established that the most significant affordance of open educational resources is the way it saves time and space for teachers, whereas lack of time and knowledge are the primary obstacles against using open educational resources. Additionally, the opinions of teachers show a demand from their employing organizations towards activities for raising awareness towards the matter of open educational resources and it has been shown that they wish to be encouraged on this matter. It has also been expressed that they expect quantitative and qualitative improvement of the resources provided by the Ministry of National Education, as well as support and cooperation on the use of open educational resources.