Purpose The aim of this study was to determine when, why, and how the presence of a word's written form during instruction aids vocabulary learning (a process known as orthographic facilitation ). Method A systematic review of the research on orthographic facilitation was carried out. PsycInfo, Web of Science, ProQuest, and OpenGrey databases were searched. The search returned 3,529 results, and 23 of these met inclusion criteria. Studies were included in the review if they were written in English, published in a peer-reviewed journal, and compared vocabulary learning outcomes when words were taught with and without their written forms. Conclusions There is strong evidence that the presence of a word's written form leads to improved learning of its spelling and spoken form. There is also some evidence that it may lead to better learning of a word's meaning. A small number of studies have also shown that the presence of a word's written form benefits vocabulary learning in children with developmental language disorder, autism, Down syndrome, and reading difficulties. However, further research into the effects of orthographic facilitation in special populations is needed. In particular, ecologically valid experiments in clinical and educational settings are required in order to better understand how exposure to a word's written form can aid naturalistic vocabulary learning.