This study examined primary school students' reading motivation and performance on the standardized exam. Participants included 901 seventh and eighth grade students from Kenya. There were 468 females and 433 males. Contrary to previous studies, results showed reading challenge and aesthetics, but not efficacy, predicted reading achievement, indicating reading motivation may not influence achievement similarly across cultures. Gender differences were found in reading achievement but not motivation, an indication of a complex relationship between reading motivation and achievement. Students who read mostly for compliance and recognition did poorly in reading. Eighth graders did better in both reading motivation and achievement.