Inquiry-based learning is a usable approach in developing gifted and talented students' learning and one that overlaps with their properties and learning needs. The aim of this research was to examine the effect of guided inquiry-based learning approach compared with that of traditional teacher-centered instruction on gifted and talented eighth grade students' understanding of acids-bases concepts and motivation towards science learning. A non-equivalent control group design was used in the research. The participants were 40 gifted and talented eighth grade students from one Science and Art Center in Ankara/Turkey. There were two different groups: the experimental group and the control group. The Acids and Bases Diagnostic Test and Students' Motivation towards Science Learning questionnaire were used in the research as data collection tools. Before and after the implementation, the tools were administered as pre-test and post-test to both groups. For data analysis the independent samples t-test and multivariate analysis of variance (MANOVA) was used. The results showed that there was a statistical significant difference between the groups in favor of the experimental group.