This research aimed to examine the effects of problem-based learning with character emphasis and naturalist intelligence on the students' critical thinking skills and curiosity. This study was conducted at Islamic Senior High School in Mataram and it employed 3x2 treatment by level design. Three treatments; the problem-based learning with character emphasis (PBL-CE) (A1), the problem-based learning (PBL) (A2), and the regular learning (RL) (A3) were given to two groups; the students with high naturalist intelligence (B1) and low naturalist intelligence (B2). The data on the students' naturalist intelligence and critical thinking were collected through the test and the data on the students' curiosity was collected through self-assessment and observation sheets. The data were analyzed using MANOVA at 0,05 significance level. The results of the study showed that: (1) the PBL-CE affect the students critical thinking skills and curiosity, (2) the naturalist intelligence does not have a significant effect on the students critical thinking skills and students curiosity, and (3) the interaction between the PBL-CE and naturalist intelligence did not affect the students critical thinking skills and curiosity. PBL-CE can be applied as alternative learning to develop students' critical thinking and curiosity.