The present study aims at examining variables (at individual and class level) that influence the accuracy of teacher judgments of second and third graders' reading abilities (decoding and reading comprehension). Data of 1,468 students and 86 teachers were collected. Due to the nested structure of the data, multilevel regression analyses were applied. Results revealed about 5% of the variance in judgment accuracy at class level. Generally, teachers judged reading comprehension abilities more accurately than decoding abilities. Low-achieving students' abilities, though, were judged less accurately. Accuracy in judging decoding was higher in small classes and in students with special educational needs. Accuracy in judging reading comprehension grew along the years (higher in Grade 3 and at the end of the academic year). Additionally, teachers judged second language learners' reading comprehension less accurately. The results are discussed in the light of implications for teacher training.