For better understanding and learning of the foreign language, it is necessary to learn its vocabulary first. With the passage of time new devices are being invented daily to meet the challenges to the modern world. Mobile phone is one of the best inventions of the twenty first century. The mobile phone not only use for communication purposes but for entertainment and teaching and learning process as well [1]. In the process of learning the mobile phone has contributed a lot, especially during covid-19. Mobile phones help students in their learning outside the classroom anywhere and anytime. The effect of using mobile phone for English vocabulary development of Pakistani secondary school students was investigated using mixed-method research design with 60 students studying in class 10th. The result of the study revealed that using mobile phone for vocabulary development is more effective than other traditional methodology.