Foreign language educators have developed measures to assess the proficiency of U.S. high school learners. Most have compared language learners to clearly defined criteria for proficiency in the language (criterion-referenced assessment) or to the performance of other monolingual English speakers (norm-referenced assessment). In this study, the performance of monolingual English students enrolled in first- (n = 293), second- (n = 268), and third-year (n = 51) high school Spanish courses on the BaterA-a III Woodcock-MuA+-oz Pruebas de aprovechamiento was compared to that of native Spanish speakers, which was normed with native Spanish speakers. Findings showed that after two years of high school Spanish, U.S. students' achievement in Spanish word decoding and spelling was similar to that of native Spanish speakers in the fifth to sixth grades, and their performance in Spanish reading comprehension, vocabulary, listening comprehension, and writing was below that of the average native Spanish speaker in first grade. Third-year students' achievement was somewhat stronger, although more similar to than different from that of the second-year students despite the added instructional time. The results are discussed in light of the U.S. social context in which monolingual English students learn to speak and comprehend a language at the same time as they are learning to read and write the language.