The purpose of this study was to investigate the extent of implementation of inquiry-based science teaching and learning in Ghanaian junior high schools. We sampled 503 students, 18 integrated science teachers, and 23 educational administrators from rural and urban areas of four districts and municipalities in the Central Region of Ghana. We used concurrent triangulation mixed methods design to collect quantitative and qualitative data. Validities, reliabilities, credibility, and dependability of the instruments were adequate. Average item means and standard deviations, frequencies, percentages, ANOVAs, Two-way MANOVA, principal component analysis, and Cronbach alphas were calculated. Thematic analysis was also conducted. We found rare implementation of inquiry-based science teaching and learning in the selected Ghanaian junior high schools. We also found significant interaction of school location and school type on the implementation of inquiry-based science instruction. Specifically, we found that code-switching of English and the local language significantly promoted the implementation of social aspect of inquiry in rural schools. We recommend more reforms in science teaching and learning in Ghanaian junior high schools to be aligned with the features of inquiry. We also recommend that code-switching of English and the local language be actively promoted in schools, especially in rural and public junior high schools.