Expectations for reading achievement in the state of Iowa require all students to be proficient by the end of third grade (ELI, 2012). This requires both teachers and principals serving elementary schools to improve reading achievement. Although teachers are proven to have the most immediate impact on student achievement, it is principals' leadership that establishes the conditions for continuous improvement. The challenges facing rural schools and the principals who serve them are well documented. They often face low enrollment, threats of consolidation, high poverty rates, and low achievement. This study examined how principals' efficacy for instructional, adaptive, and transformational leadership effects third grade reading achievement in rural Iowa schools. The conceptual framework used for this study combined Albert Bandura's (1977) sources of self-efficacy with Mary Hooper and Victoria Bernhardt's (2016) trimodal leadership model. Elementary principals from Iowa made up the sample participants for this study. Both rural and non-rural principals participated in this survey, with a total of 92 participants. Results indicated that there was no significant difference between rural and non-rural principals based on third grade reading achievement over a three year period from 2016 to 2018. Multiple regression analysis indicated that efficacy for instructional, adaptive, and transformational leadership were not significant predictors of third grade reading achievement. Hierarchical regression results showed that mastery experience -- principals who experienced success while implementing improvement efforts in reading; and verbal persuasion -- principals who utilized the advice from a literacy expert or coach, were significant predictors of principals' sense of efficacy. Recommendations for policy and practice are included to both develop principals' perceived capability and learning opportunities to improve achievement. [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.]