This study aims to explore the affordances offered by online role-playing games like RuneScape in learning English vocabulary and developing reading skills, and to examine whether there is any relationship between playing RuneScape and Korean children's vocabulary and reading skills. I sampled five elementary students (1 female and 4 males, aged 10-11), who played RuneScape for 30 minutes per session for 9 to 14 sessions in a private English institute in South Korea. I collected the text data through retrieving the text from the recordings of participants’ game-plays using a screen recorder. The observation data was attained by observing them playing games through participant observation, observation framework and field notes. I analysed the English text learners would encounter when playing Runescape, and using observation, attempted to describe the vocabulary and reading strategies they tend to use whilst playing. The findings showed that participants encountered the seven categories of vocabulary whilst playing: generally-used vocabulary, fixed phrases, RuneScape vernacular, lexis specific to computer games, chat speak (acronyms and abbreviations), emoticons and reduplication. From the observation data, I found that participants used the following vocabulary strategies: looking up in a dictionary, verbalising vocabulary and guessing meanings verbally. Reading strategies were: clicking, verbalising, reading texts aloud, translating and typing. The findings suggest that there is relationship between playing RuneScape and vocabulary and reading skills. However, Korean children do not get sufficient practice in their use of vocabulary and reading skills for pragmatic purposes in their English classrooms, due to time limitations and large classes. Children tend to lack instrumental motivation for learning English, so the fun and interest of playing games might help engage them in learning English. I would argue therefore that online role-playing games have the potential for Korean children as a useful supplementary tool for developing vocabulary and reading skills.