A central focus in remedial teaching is the generalisation of responses to contexts in which a student has never been explicitly instructed. Remarkably little is known about how and when generalisation occurs. In this article we examine generalisation effects in the context of spelling. Three areas are discussed: generalisation between spelling and reading, generalisation to untrained sound-letter-correspondences and generalisation to untrained unpredictable words. The research presented indicates both that reading training often leads to spelling improvements and that spelling training leads to reading improvements. There is a tendency for spelling training to be more likely to induce changes in reading than vice versa. In addition, for unpredictable words, generalisation is more likely to occur for words of high frequency and words that are orthographically similar to many other words. We conclude that a better understanding of how generalisation occurs will enable us to improve the efficiency and effectiveness of remedial spelling programmes.