The modern media industry is characterised by widespread adoption of new media technologies. With social media tools, media practitioners enjoy a wide variety of story sources and ways of presenting news. However, the hugely unregulated online environment has presented numerous ethical challenges for online reporting – misinformation, fake news, invasion of privacy and cyber-bullying among others. In journalism training, future media professionals are constantly reminded of the principles of online ethical reporting and how they adhere to them. It has also been argued that engagement with Social Networking Sites (SNSs) has professional learning effects, especially for journalism students. This paper departs from this argument and explores how students’ SNSs usage behaviour predicts their beliefs in their ability to ethically work in online environments after graduation. Using a sample of 143 journalism final year students drawn from five Rwandan universities, the study interrogates the relationship between the students’ choice of SNSs, frequency of SNSs usage, level of engagement with online audiences, incidental experiences on content shared and their self-efficacy for journalism netiquette. Gender differences in this relationship are also explored to establish how male and female students perceive their confidence to handle ethical issues in the online industry. Findings show that most of the respondents are active users of SNSs, with weak to moderate correlation of this SNS usage behaviour on their self-efficacy for journalism netiquette. While SNS usage behaviour was found to have a 23.6% explanatory power on the students’ journalism netiquette self-efficacy, gender differences were not significant (1.4%). The findings suggest a more deliberate effort to harness students’ day-to-day SNSs use experiences (e.g. in class-based online ethics case studies) in preparing the future professionals to handle such ethical cases in practice.