Sound symbolism is the phenomenon of cross-modal correspondences non-arbitrarily linking phonological components and semantic meanings in language (e.g., words meaning round contain a high proportion of rounded vowels such as /u/; Mathur, 2010). Our study suggests that this cross-modal phenomenon is related to synaesthesia, a cross-modal phenomenon wherein one sensory or cognitive stimulus (e.g., the written word jail) causes the experience of an additional percept in the same modality (e.g., the colour pink) or across modalities (e.g., the taste of chocolate). In Experiment 1, we found that grapheme-colour synaesthetes (synaesthetes that experience colours in association with letters and/or numbers) were better at determining the meanings of sound symbolic foreign words than nonsynaesthetes, suggesting that synaesthetes possess heightened skills in domains unrelated to their specific form of synaesthesia. In Experiment 2, we discovered that the word-taste associations of lexical-gustatory synaesthete JIW abide by sound symbolic rules, which nonsynaesthetes’ sound-taste associations also follow. Together, these experiments support a relationship between sound symbolism and synaesthesia likely arising from a common set of cross-modal mechanisms. Our paper discusses the implications of these results for the relationship between sound symbolism and synaesthesia as well as for each individual phenomenon.