The rapid development of social media has provided micro, small, and medium enterprises (MSMEs) with opportunities to expand their markets and strengthen interactions with consumers. However, digital promotion also raises ethical concerns, including incomplete product information, exaggerated claims, unverifiable testimonials, and inadequate protection of consumer data. This study aims to analyze the application of business ethics in MSME product promotion on social media and its relationship with consumer trust, loyalty, and business sustainability. This study employed a literature review using a descriptive qualitative approach. The data were drawn from 25 scientific articles published between 2018 and 2025 and retrieved from Google Scholar, Crossref, Garuda, and the Directory of Open Access Journals. The data were analyzed thematically through the identification, classification, comparison, and interpretation of previous research findings. The results revealed four main ethical principles in MSME digital promotion: honesty, transparency, responsibility, and fairness. Applying these principles was associated with consumer trust, satisfaction, repeat purchases, positive recommendations, and loyalty. Nevertheless, their implementation remains constrained by limited digital literacy, intense market competition, exaggerated promotional claims, and unprofessional complaint management. This study concludes that business ethics should be integrated into digital marketing strategies to strengthen the reputation and long-term sustainability of MSMEs.