The relationship between language and space has been intensely investigated. The underlying question has been whether one affects the other, usually within the scope of spatial language. Largely ignored is the possible role of bilingualism. Given that the average person speaks more than one language, and the mounting evidence showing that bilingualism interacts with non-linguistic processes (e.g., Bialystok & Senman, 2004), we investigated what effect bilingualism would have on non-linguistic spatial processing. We tested 120 participants with a range of linguistic abilities using four classic spatial tasks, e.g. mental rotation. We found patterns of systematic interaction between bilingualism and spatial processing. These findings raise questions beyond the relationship between spatial language and spatial cognition, suggesting that language as a cognitive process may share a common neural substrate with space.