Various studies suggest that covariational reasoning plays an important role on understanding the fundamental ideas of calculus and modeling dynamic functional events. The purpose of this study was to investigate a group of mathematics teachers' covariational reasoning abilities and predictions about their students. Data were collected through interviews conducted with five secondary mathematics teachers to reveal about their covariational reasoning abilities as they worked through a model-eliciting activity, predictions about their students' possible approaches to solve the given problem, possible mistakes in solving the problem, and misconceptions they possibly held. The results showed that not only the teachers' covariational reasoning abilities were weak and lack depth but also their predictions about students' reasoning abilities bounded by their own thoughts related to the problem. © 2010 Eǧitim Danişmanliǧi ve Araştirmalari İletişim Hizmetleri Tic. Ltd. Şti.