Asynchronous online learning is well documented with adults, but fewer studies of effectiveness have emphasized elementary education learning environments. This study investigated student achievement on the Texas Assessment of Knowledge and Skills (TAKS) test for fifth grade students who had participated in synchronous and asynchronous courses using a quasi-experimental design. TAKS scores were compared using an analysis of covariance to show initial differences in a pretest of targeted mathematic skills, and performance gains on the TAKS were found to be similar for the asynchronous and synchronous online learning groups. Responses to a questionnaire on students' attitudes toward learning in an asynchronous online environment revealed that students shared similar attitudes about working independently and working with assistance from the teacher, regardless of the learning environment. The results of this study indicate that the learning environment (synchronous vs. asynchronous) does not influence student performance on the TAKS, regardless of gender, socio-economic status, or student attitude towards interacting within an asynchronous online learning environment. Generalizing of findings is limited because of the sample size (n=40). Only two groups of students at one elementary school were sampled. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]