Scholarly writing has been documented by nursing leaders and faculty as vitally important to nursing education and professional development. However, a lack of standardized guidelines on the use of tutorials and resources for promoting effective scholarly writing in RN-BSN completion programs remains unclear. The purpose of this study was to assess the impact of a scholarly writing tutorial on scholarly writing assignment rubric scores in an online, RN-BSN completion program. The study hypothesized the use of an interactive, online scholarly writing tutorial could impact rubric score grades, spelling and grammar, and APA style, on a writing assignment with the use of Knowles’ Adult Learning Theory as the theoretical framework. The study used a quantitative, non-experimental, before and after design to compare median rubric scores between a pre-intervention group (n = 108) and a post-intervention group (n = 56) at a major metropolitan university in the southern U.S. A Mann-Whitney U test revealed a statistically significant difference in both the median spelling and grammar rubric scores (p = .03; r = .15) and APA style rubric scores (p = .02; r = .11) of RN-BSN nursing students between the pre-intervention and post-intervention groups. The study results strongly support the use of an interactive, online scholarly writing tutorial structured with Knowles’ Adult Learning Theory to enhance student success with writing mechanics and APA style.