We feel great pleasure to present this book “IJSO - International Junior Science Olympiad Solved Papers (2008 to 2019)” before you. Wherein, we have made an attempt to provide previous years solved exam papers of IJSO (International Junior Science Olympiad) with answers and complete solutions of questions. Solutions to the questions have been written in such a manner that the students will be able to understand the application of the concepts and can answer some other related questions too.