Grit and mindset are two of the hottest topics in education today, but research on their predictive power for academic success is inconclusive and rife with gaps and limitations. The purpose of this study is to investigate the relationships between grit, mindset, self-regulated learning (SRL), and academic outcomes for adult students attending online colleges. This was investigated using data from the Diagnostic Assessment and Achievement of College Skills (DAACS) project, and includes 9,276 undergraduate, mostly adult students from two online institutions in the United States. The results indicate that while grit, its two components, and mindset were significantly correlated with each other and SRL, none of them were significantly, positively predictive of any academic outcomes, including success rate, on-time progress, and retention. Explanations, limitations, and the scholarly significance of the study are explored. [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.]