This study assessed the plausibility of using Ajzen's (1991) theory of planned behavior (TPB) to identify the factors that motivate adults to participate in Adult Basic Education (ABE) classes at a Southeast Wisconsin Community College. The original TPB (Ajzen, 1991) attests that planned behaviors are determined by behavioral intentions which are largely influenced by three determinants: attitude (a student's overall evaluation of enrolling in ABE classes), subjective norm (a student's own estimate of the social pressure from people they care about regarding participating in ABE classes), and perceived behavioral control (the extent to which a student feels able to engage in ABE classes). This study explored the relevance of incorporating Bandura's (1997) general self-efficacy (a student's perception of their ability to participate in ABE classes) as one of the three determinants in the TPB instead of using the determinant of perceived behavioral control. Like attitude and subjective norm, general self-efficacy assumes that goal directed behavior is a purposive action rooted in cognitive activity. The postulate central to this theory is that adult's process information and thereby self regulate their motivational orientations. Thus, in this study, motivational orientations are the cognitive representation of a student's reason to enroll in ABE classes and are the immediate antecedent of behavior that is influenced by the three determinants of the modified TPB: attitude, subjective norm, and general self-efficacy. To fulfill the objectives of this study a cross sectional paper and pencil survey, consisting of five data collection questionnaires with a total of 80 questions, was administered. The data collection for the study occurred during the Fall 2012 semester, starting on August 23, 2012, and ending on September 27, 2012. The final sample size was 600 research participants (n = 600). The study found that attitude, subjective norm, and general self-efficacy were statistically significant and positively correlated to motivational orientations. The results of the study provide the scientific validation of the power of the TPB and suggest its specificity, in which the determinants of attitude, subjective norm, and general self-efficacy can be used to identify the motivational orientations of adult students enrolled in ABE classes. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]