This study describes the creation and validation of an adaptive and self-applied test of lexicon in Spanish for kindergarten to eighth-grade basic school students. Using a corpus of 1,000,000 words from school texts, some words with different frequency and difficulty were selected. The test items were prepared according to the test format PPVT [Peabody Picture Vocabulary Test], representing each word with pictures. The distractors were generated randomly from the same corpus. The construct validity, concurrent validity and internal consistency were determined. EVOC is a valid and reliable instrument to evaluate the lexicon in Spanish that allows adapting the pedagogical practices to the student's needs.