The paper describes an action research being developed by the researcher to "address the issue of plagiarism and" assist tertiary students to master second-language (L2) writing using sources in a higher education institute (HEI) in Oman. It recruited 16 undergraduate students from two classes who undertook an L2 writing course. To identify their needs of citation skills and develop a follow-up action plan, the students were initially asked to write a referenced-based essay, and then they were interviewed to explore their knowledge and skills of citation. Accordingly, specific amount of tasks were developed and conducted in 10 weeks. After implementing the tasks, the participants were asked to write another referenced-based essay and then they were interviewed for the second time to explore any change they had in knowledge and skills of citation. Findings showed that instances of plagiarism significantly decreased in their second essay; however, there was a modest overall improvement in cases of misinterpreted citations across the students who had low level of English proficiency. Implications for teaching citation skills in academic L2 writing contexts are discussed.