The purpose of this study was to determine the effect of teacher expectations on first-grade reading achievement. Rankings of reading readiness were collected from 26 classroom teachers before and after falsified reading readiness scores were presented to them. From 536 first graders, 32 high socioeconomic status with low reading readiness status pupils and 32 low socioeconomic status with low reading readiness status pupils were randomly selected. Positively falsified reading readiness scores were reported to the teachers for 16 children from each of these groups. The remaining 32 children served as control groups. The Stanford Achievement Test (SAT), Primary One Battery, Form W, was administered to all children in the 26 classrooms eight weeks later. The SAT, Primary One Battery, Form X, was administered to all children in the 26 classrooms six months after falsified readiness data were given to the teachers. The results indicated that there were no significant differences in word reading or paragraph meaning scores between the experimental and control groups, or between the interactions for either analysis of the SAT scores. Also, teacher rankings of reading readiness are as reliable as using the Metropolitan Readiness Tests, Form B. (Author/WR)