The current study investigated the elementary school classroom teachers’ opinions about constructivist learning environments. The current study employed the mixed method. The study was conducted with the participation of randomly selected classroom teachers working in state elementary schools in the district of Bagcılar in İstanbul. As the data collection tools in the study, “Constructivist Learning Environment Scale” developed by Tenenbaum et al. (2001) and adapted to Turkish by Fer and Cırık (2006), a personal information form and 6 open-ended questions developed by the researchers were used. In the analysis of the collected data, SPSS program package, NVivo 11 and content analysis method were used. The findings of the analyses revealed that the classroom teachers’ opinions about constructivist learning environment do not significantly vary depending on gender, year of graduation from university, socio-economic conditions of the environment where their school is located, whether they have undergone in-service training about constructivist learning approaches; yet, they vary significantly depending on professional experience and the grade levels in which they are teaching. Teachers’ professional experiences are effective in the process of recognizing the learners’ needs in their classrooms and constructing teaching-learning designs suitable for these needs. It was understood that the fourth year students attach more importance to discussions and negotiations and sharing of opinions in terms of establishing constructivist environments in their classes. It was concluded from the face-to-face interviews conducted with the classroom teachers that their professional competencies are at the desired level; therefore, they experience difficulties in implementing constructivist approaches and they cannot take their desired benefits from in-service training programs they have participated in. The constructivist learning classrooms organized by teachers adapting to constructivist learning approach are gaining greater importance