The research aimed at studying the effectiveness of Web Quests in learning science to develop the scholastic achievement and the skill of the environmental decision making for the preparatory stage pupils. The Web Quests were planned to be lessons. The study was applied to an intentional subject of (82) pupils, prep two. It was divided into an experimental group (40 pupils) and a control group (42 pupils). The researcher used the experimental method with two equivalent groups (experimental and control). The Web Quests were used with the experimental group, where the control group used the traditional technique of learning. The research tools, such as an achievement test, the measure of the environmental decision making, were applied. The results showed a statistically significant difference between the average score of the two groups on the post application in favour of the experimental group. This result confirms the effectiveness of Web Quests in developing the scholastic achievement and the skill of decision making.