This research is Classroom Action Research (CAR), which was implemented withlesson study that was carried out in 2 cycles in the period ofJanuary 10, 2014 to March 12, 2014.The objectives of this research are to improve the science process skills, metacognitive skills andlearning outcomes of biology by implementation of guided inquiry method. The results showedthat the implementation of the method guided inquiry-based lesson study can improve student'sscience process skills by 18.9%; metacognitive skills boost by 4.93%; cognitive learningoutcomes by 6.64%, affective related to social attitudes ofstudents by 9.37% and affective relatedto material Respiratory System and Excretion by 3.27%.