This study explored the process of how Malay primary ESL learners build English vocabulary using multimedia technology. With this purpose, students’ choices of multimedia technology tools and the reasons behind the choices were investigated. The qualitative approach was employed in this study by conducting semi-structured interviews with three Malay primary school students aged 12 years old from a public school in Kuala Lumpur. The findings revealed that the students chose three main types of multimedia tools namely audio, audio-visual, and video games. The participants revealed three reasons behind their preferences of the multimedia tools which are acquisition of additional information, presence of visuals, and convenience. It was also found that the process of vocabulary-building using the preferred multimedia tools can be organised into four stages namely (i) first encounter, (ii) cognitive dissonance, (iii) establishing equilibrium, and (iv) remembering. The findings suggest English teachers to include multimedia tools in the teaching of vocabulary because it facilitates the process of vocabulary building among students as the words are learned in context and enhanced with visuals.