J. R. R. Tolkien once said of The Hobbit (1937), ‘One writes such a story […] out of the leafmould of the mind.’ Referring to fertile compost made up of decaying leaves, the word mould can also describe a container that gives shape to liquids as they solidify. Unfortunately, all too many readers respond to Tolkien’s work according to the latter definition, picking and choosing passages out of context to fit them into a pre-established thesis. The same has been done to the fiction of Tolkien’s fellow Inklings, an Oxford writers’ group he helped form in the early 1930s. In contrast, this chapter attempts to honour Tolkien’s definition of leaf-mould in order to demonstrate how George MacDonald fertilised the imaginations of multiple Inklings. It focuses particularly on how Tolkien, C. S. Lewis, and Charles Williams read MacDonald and how MacDonald’s thought and writing provided a fertile ground in which their own writings could take root.