L2 lexical studies have established that learners need to acquire knowledge of the first 3,000 most frequent words in order to enjoy 95% coverage of the vocabulary used in spontaneous speech (Nation 2006). However, there has been little data available that reveal how many of these most frequent words can be recognized by university language majors, with Robles-García´s (2020a, 2020b) recent study being a welcome exception. The present inquiry into L2 vocabulary gains employed the same word-recognition test developed by Robles-García (2020a) in order to characterize the vocabulary size enjoyed by upper-division Spanish majors, both non-native and bilingual native (i.e., heritage) speakers, enrolled in a California public university. The results show that non-native Spanish majors in their third and fourth year of the major are still struggling to learn the first 3,000 most frequent Spanish words. In contrast, the heritage students demonstrated strong word recognition of almost all of the words in this basic inventory. The curricular implications of these results are discussed with respect to both non-native and bilingual native Spanish majors and an argument is made for continued explicit vocabulary instruction throughout the upper-division program.