Reading in difficult or novel fonts results in slower and less efficient reading (Slattery & Rayner, 2010); however, these fonts may also lead to better learning and memory (Diemand-Yauman, Oppenheimer, & Vaughan, 2011). This effect is consistent with a desirable difficulty effect such that more effort during encoding results in better long term retention (Bjork, 1994). The effect is robust and found in many contexts; however, it has not yet been applied to the process of lexical acquisition. The purpose of the current study was to investigate whether readers would learn words better when presented in Sans Forgetica, a font designed to induce desirable difficulty. One hundred sixty participants were randomly assigned to one font type and read sentences with 15 very low-frequency English words presented in two different informative contexts while their eye movements were monitored. They completed a spelling skill assessment and tests of their orthographic and semantic acquisition of the words. Linear mixed effects analyses were conducted and indicate that high-skill spellers learned the spelling and meaning of words better in the desirable difficulty font, but low-skill spellers did not show the same benefit. This pattern highlights the importance of individual differences in learning such that a desirable difficulty for one reader may be an undesirable difficulty for another.