Contact with nature can have numerous beneficial effects for children. As the school is a place where children spend a lot of time, the physical environment of the school has considerable potential to influence children. This study investigated the influence of a redesign (greening) of a schoolyard on pupils’ physiological stress, psychological well-being, and executive functioning. A pre–post, quasi-experimental design with a multimethod approach was applied. One-hundred thirty-three middle school pupils (M = 14.4 years) of three middle schools in a rural area in Austria were assessed. The renovated schoolyard significantly diminished pupils’ physiological stress levels and enhanced their psychological well-being. Pupils in the renovated schoolyard setting also perceived the environment as more restorative following the redesign. However, it did not affect executive functioning as hypothesized. Limitations of the study and future research opportunities are discussed.