Instruction manuals need to explain specialized technical information to readers of the general public. Using metadiscourse effectively, i.e. engaging with readers and guiding them through the text, is therefore crucial for successful communication. An increased awareness of how these features are used in instruction manuals would therefore help technical writers write reader-friendly texts. This study investigates metadiscourse in ten instruction manuals in English using Hyland’s (2005) taxonomy. It was found that the interactive metadiscourse is predominated by frame markers and code glosses, which reflects the purpose of instruction manuals to explain clearly and efficiently how a machine works. The interactional metadiscourse reflects the twofold relationship between the writers and their readers: on the one hand, that of instructor and inexperienced users of the product and, on the other, that of manufacturer and customer. The former is reflected by the frequent usage of necessity attitude markers and boosters to reinforce instructions and precautions. The latter is reflected by the usage of politeness markers and the hedging of problems and risks. The visual presentation of the manuals, i.e. its segmentation, typographical variation, punctuation and illustrations, was also shown to express metadiscourse meanings.