The effects of sex and tutorial instructions were studied as they influence the hour concept development of the pre-school child. The research was conducted at Utah State University Child Development Laboratories with twenty-two, three to five-year-old children enrolled at the time. Each child received three training sessions with the author. It was found that the twenty-two children who had received individualized instruction on the hour concept showed a significant concept of a clock when the large hand was always constant on the numeral twelve. The findings indicate that there was no significant difference between boys and girls on their ability to retain the hour concept from post-test 1 to post-test 2. No significant difference was found in the learning ability between boys and girls in this study.