It has long been theorized, if not exhaustively researched, that bilingualism and biliteracy are beneficial in promoting linguistic and academic gains; but the operationalization of these constructs is confounding. In the current study, the authors worked with 118 Spanish-English bilingual Latina/o students and investigated whether Spanish-English biliteracy (vs. English monoliteracy) was associated with stronger performance on three English metalinguistic measures. Results indicated an effect of biliteracy on these measures; however, English predictors were confounded with the biliteracy indicator, making results difficult to interpret. The authors argue that new measures that tap bilingualism and biliteracy as a single construct are necessary to move the field forward. (Contains 1 note and 2 tables.)