The study was conducted to find out the effectiveness of structural method of teaching vocabulary in English subject at secondary level. The population of the study was the students of secondary classes studying in Federal Government schools of Islamabad District. Purposive and random sampling techniques were applied to select the school, teachers and the subjects. Pretest-posttest Control Group design was used for this study. The study revealed that there was significant difference between the performance of the students taught with the structural method of teaching vocabulary (SMTV) and taught with the definitional method of teaching vocabulary (DMTV). The high, average and low achievers of experimental group performed better as compared to the performance of the students who were taught with the DMTV vocabulary. The better performance in all the categories of the experimental group was due to the morphological analyses of a word, experimenting with the word, role of the students as the partner in the learning process, management of the learning by the students themselves, generation and active processing of vocabulary, provision of multiple exposure of different intensity for practice and personalization of word learning.