The purpose of this study was to investigate and compare the impact of task-based instruction (TBI) and traditional instruction (TI) on the motivation and vocabulary development in secondary language education. The focus of the study was to also find out the perceptions of teachers about implementing these two instructional methods in their teaching practices. The participants were 97 students and 2 teachers engaged in the 7th grade EFL program at a private school in Istanbul, Turkey. Data was collected quantitatively from a vocabulary check test and motivation scale, as well as qualitatively from semi-structured interviews. The findings revealed that implementing TBI had positive impact on students' vocabulary development as well as their motivation. In line with these findings, it was also suggested that teachers perceived TBI to be a more effective method to be incorporated in secondary grade language practices. Based on the gathered findings, suggestions for redesigning and implementing the existing 7th grade EFL program were provided.