This study examined how teachers perceive the incorporation and use of computer technology resources in language teaching through investigation of teachers’ attitudes and approaches to using an online supplementary resource in vocabulary instruction in an EFL context. The program offers such tools as vocabulary level tests, a vocabulary frequency profiler, word and text concordancer, and cloze text and hypertext builder. The aim of the study was to explore the factors that affect teachers’ use or non-use of the online program for teaching purposes. The study finally examined whether and to what extent opportunities, facilities, and training provided to teachers contribute to their acceptance and use of these resources. The data was collected through questionnaires distributed to 97 teachers in an English-medium university. Based on the results of the questionnaires, a stratified sample of 12 teachers was selected for follow-up interviews. The questionnaire results revealed statistically significant differences between teachers who have undergone computer technology training and those who have not in terms of their attitudes toward computers and the use of computer technology resources in language teaching. Follow-up interviews were used to determine whether positive attitudes or interests led people to undergo training or the reverse. The responses supported both cases for different individuals. The results also showed that simply introducing computer technology resources does not guarantee teachers’ use of these in practice. The provision of training is seen as a key factor in both changing attitudes and encouraging teachers in incorporating technology into their instruction.