The purpose of this study was to investigate the effect of Process Oriented Guided Inquiry Learning (POGIL) method compared to traditional teaching method on 11th grade students' conceptual understanding of electrochemistry concepts. Participants were 115 students from a public school in Turkey. Nonequivalent control group design was used. Two experimental groups and two control groups were randomly selected. The experimental groups were taught using the POGIL method, while control groups were taught using the traditional teaching method. An Electrochemistry Concept Test (ECT) was administered to both groups as a pre-test and post-test in order to assess the students' misconceptions and their conceptual understanding of electrochemistry concepts. Gain scores were compared using independent-samples t-test. The results showed that the POGIL method resulted in a better acquisition of scientific conceptions and in changing misconceptions in electrochemistry concepts than with traditional teaching methods.