The objective of this research was to find out whether or not inquiry learning could improve students' ability in writing report paragraph. The researcher applied pre-experimental research design which was conducted by using pre test and post test. The sample was the eleventh grade students of SMK Negeri 4 Palu, the researcher took one class of the sample. It was XI D Keperawatan. It consisted of 10 students. The sample is called total sampling. In this research, the researcher used test to measure the students' skill in writing. The results of this research showed that the t-counted value was 15.02 while t-table value was 2.26. Based on the analysis result, t-counted value was higher than the t-table value (15.02>2.26), therefore the hypothesis of this research was accepted. It means that inquiry learning can improve the eleventh grade students' skill in writing report paragraph of SMK Negeri 4 Palu.
Keywords: Improving; Writing Skill; Report Paragraph; Inquiry Learning.