The study aimed to find out the students' perceptions and the factors influencing students' perceptions toward the use of mobile application in learning English particularly speaking. In the study, case study research method was used based on qualitative data. The data were collected through semi-structured interview forms and an observation sheet developed by the researchers. The participants were five vocational school students who were selected via purposive method in Surakarta, Central Java, Indonesia. The participants had been familiar with mobile application and they had been taught speaking English using mobile application by their teacher, so that they could give adequate information. The findings showed positive perception from the students toward using "Learn English Conversation" application in learning speaking. They declared that the use of Learn English Conversation application could facilitate them in practicing speaking, bring fun and enjoyable learning during the learning process. Moreover, their positive perceptions were influenced by several factors such as the flexibility and the new learning experience given by the mobile application, the ease to run the mobile application and unrequired a lot of internet quota when the students run the mobile application.