The Effects of STS-Infusion Instruction in Science on Fifth Graders¡¦ Learning Attitude, Critical Thinking, and Technological Creativity Abstract The main objectives of this study were to explore (a) the effects of STS-infusing instruction in science on learning attitude, critical thinking, and technological creativity; and (b) the relationships among learning attitude, critical thinking, and technological creativity. An unequal group pretest-posttest design was employed in this study. Eight fifth-grade classes of a public elementary school in Taina were selected based on purposive sampling. The participants were divided into the experimental group (n = 79 ) and the control group (n = 78 ). The experimental group received a twelve¡Vweek STS-Infusion instruction in the subject of Science, while the control group received regular instruction. The employed instruments included The Test of Technological Creativity, Critical Thinking Test¡XLevel I, The Questionnaire of Learning Attitude on Science, and the Questionnaire of Teaching Feedback. The analysis methods included Descriptive Statistics, t-test, Multivariate Analysis of Variance, Univariate Analysis of Variance, Multivariate Analysis of Covariance, and Multiple Stepwise Regression. The main findings in this study were: (a) the STS-Infusion Instruction had significant effects on upgrading the fifth graders¡¦ learning attitude toward Science; (b) the STS-Infusion Instruction did not have significant effects on improving the fifth graders¡¦ critical-thinking abilities; (c) the STS-Infusion Instruction had significant effects on improving the fifth graders¡¦ technological creativity; (d) students with different level of learning attitude toward Science did not perform differently on technological creativity; (e) students with different level of critical-thinking abilities did not perform differently on technological creativity; and (f) the STS instruction, critical-thinking abilities, and learning attitude toward Science could effectively predict the fifth graders¡¦ technological creativity. Finally, some suggestions were proposed for educational authorities, teachers, and future researchers.