The research aimed to reveal the level of both the constructivist learning environment and discovery learning, from the perspective of Bruner's model of cognitive development, and the possibility of the constructivist learning environment contributing to the prediction of discovery learning, among a sample of 414 third-year preparatory students from schools in the West Zagazig Educational Administration in Sharqia Governorate. The constructivist learning environment scales (co-control, student negotiation, interpersonal connection, uncertainty, and critical voice) and the discovery learning scale were applied to them. Using a one-sample t-test, the results indicated that the level of both the constructivist learning environment and discovery learning was below average. Using multiple linear regression analysis, the results indicated the inclusion of four independent variables in the regression model: uncertainty, interpersonal connection, student negotiation, and critical voice. These variables contribute to the prediction of discovery learning with a variance of 46.4% and have a significant impact on discovery learning. The non-standard regression equation and the standard regression equation were derived, which is useful in generalizing the results to other samples from the same original population as the current research sample. Keywords: Constructivist Learning Environments, Discovery learning, Bruner's model Cognitive Growth, Middle School Students