This study aims to present the validation of a test designed to assess young learners’ general L2 English vocabulary knowledge, the Young Learner Vocabulary Assessment Test (YLVAT). YLVAT consists of 37 items selected from the K1–2 frequency levels of the Productive and Vocabulary Levels Tests. In the study, Swedish learners (N = 52, age 12) took YLVAT and filled out an evaluation; scores from the national test of English (readingand listening comprehension) were also collected. Four validity measurements were used: the spread of YLVAT scores, correlation with the national test – reading, correlation with the national test – listening, and evaluation responses. YLVAT results point to a sufficient spread of scores (M = 18.9, SD = 6.5). There were significant correlations between YLVAT and (i) reading (r = .597**), (ii) listening (r = .541**), (iii) perceived test difficulty (r_s = -.538**), and (iv) how fun it was to take the test (r_s = .683**). An ANOVA showed that learners who found YLVAT “easy” or “very easy” scored significantly (p = .000) higher (26.1) than those who found it “difficult” (18.3) or “very difficult” (12.9). Finally, teachers found YLVAT to correlate with their own assessment of learners’vocabulary.