Teaching vocabulary to primary grade children is essential. Previous studies of teaching vocabulary (word meanings) using story books in the primary grades reported gains of 20%-25% of word meanings taught. The present studies concern possible influences on word meaning acquisition during instruction (Study 1) and increasing the percentage and number of word meanings acquired (Study 2). Both studies were conducted in a working-class school with approximately 50% English-language learners. The regular classroom teachers worked with their whole classes in these studies. In Study 1, average gains of 12% of word meanings were obtained using repeated reading. Adding word explanations added a 10% gain for a total gain of 22%. Pretesting had no effect on gains. In Study 2, results showed learning of 41% of word meanings taught. At this rate of learning word meanings taught, it would be possible for children to learn 400 word meanings a year if 1,000 word meanings were taught. The feasibility of teaching vocabulary to primary grade children is discussed.