Fairly little is known about the importance of phonological and orthographic processing abilities for reading and spelling in monolingual and bilingual adults. This study compared these underlying abilities, employing a range of phonological and orthographic tasks, in English monolingual (n = 28), English first language and Chinese second language bilingual (n = 21), and Chinese first language and English second language bilingual adults (n = 22) who were equally skilled in reading and spelling English, and explored the contributions of these abilities to English word reading and spelling for each group. The results displayed group differences in phonological processing, with English monolingual adults having better phonological abilities than both groups of bilingual adults. No significant group differences were found for orthographic processing. Regression assays displayed phonological abilities were a unique predictor of English word reading for both bilingual groups, but not for the English monolingual group. Orthographic skills were a significant predictor of English word spelling, but only for the English monolingual adults. This proposes there may be a long-lasting impact of being exposed to two contrasting languages on abilities underlying literacy in bilingual individuals.