Start-ups are particularly interesting due to their dynamism and proactive adaptation of business models to evolving contexts. Recent pressures to focus on environmental, social, and financial sustainability have further stimulated their innovative capacities. This study conducts a systematic literature review on environmental and social sustainability to examine innovative start-ups that strongly integrate sustainability principles into their corporate strategies and business models. We explore how the sustainability orientation of start-ups has evolved over time (RQ1), identify driving factors and barriers (RQ2), and assess the tools used to improve sustainability performance accountability (RQ3). Our findings reveal that sustainability orientation is becoming a key factor in evaluating start-ups, affecting their performance, corporate disclosure quality, and competitiveness in the market. With both theoretical and practical implications, this work advances the understanding of sustainability in start-ups, identifies challenges, and provides actionable insights for policymakers and managers. It underscores the importance of fostering sustainability-oriented innovation for long-term competitiveness and environmental resilience.