Following usage-based views on language learning, input that learners are exposed to is the foundation of the linguistic features that are acquired. Inspired by the essential role of vocabulary for comprehension, studies have determined the vocabulary demands of various sources of input (e.g., novels, movies), but many questions remain regarding L2 textbooks, a central component of L2 classroom input. Moreover, current research into L2 textbooks has focused exclusively on English as L2. Flanders presents a unique case in that there are two main foreign languages: English and French. Therefore, a cross-lingual corpus consisting of English and French L2 textbook reading materials was compiled (ca. 300,000 words per L2) in order to investigate what the vocabulary demands are (= RQ1), how the demands evolve across secondary education (= RQ2), and how target language influences the (evolution of) demands (= RQ3). A custom Python script was developed to calculate lexical profiles, i.e., categorisations of the textbooks' vocabulary into word frequency lists. Typically, lexical profiling research relies on word families as lexical unit, but we opted for lemmas instead in light of the higher morphological demands of French. Results showed that knowledge of the 11,000 most frequent lemmas was required to reach unassisted comprehension of the first grade English materials, as opposed to 18,000 for French. From there, English shows a systematic and fairly gradual increase in vocabulary demands across grade levels, whereas French demands seem to fluctuate, an evolution which could hinder French L2 development. Pedagogical implications will be addressed.