The significance of the Agile manifesto in software development lies in its foundational principles that prioritize customer collaboration, adaptability, and delivering functional software over rigid planning. It emphasizes creating value through iterative development and frequent feedback, encouraging teams to respond to change rather than strictly adhering to initial plans. The manifesto articulates key values—individuals and interactions, working software, customer collaboration, and responding to change—that guide Agile methodologies like Scrum and Kanban. Ultimately, it fosters a culture focused on continuous improvement, higher quality products, and stronger stakeholder engagement.