A connection to nature index was developed and tested to measure children’s affective attitude toward the natural environment. The index was employed through a survey that investigates students’ attitude toward Lagoon Quest, a mandatory environmental education program for all fourth-grade, public school students in Brevard County, Florida. Factor analyses were conducted to explore and confirm different factors in the connection to nature index. A path analysis was conducted to examine the association among variables. The results suggest four dimensions in the children’s connection to nature index: (a) enjoyment of nature, (b) empathy for creatures, (c) sense of oneness, and (d) sense of responsibility. Children’s connection to nature influences their intention to participate in nature-based activities in the future. Children’s connection to nature, their previous experience in nature, their perceived family value toward nature, and their perceived control positively influenced their interest in performing environmentally friendly behaviors.