The exponential growth of IoT devices has created unprecedented security challenges, particularly in device authentication where traditional methods expose sensitive credentials and lack scalability. This paper presents a comprehensive authentication framework integrating Zero-Knowledge Proofs (ZKPs) with Physical Unclonable Functions (PUFs) to achieve privacy preserving device authentication. Our framework employs zk-SNARKs for efficient proof generation and verification while leveraging PUF-derived hardware-rooted identities for unclonable device fingerprints. Experimental evaluation demonstrates 20% energy reduction compared to RSA-2048, 19ms verification time, and 100% success rate across varying environmental conditions. The framework supports over 10,000 devices per verifier node while maintaining strong security against replay attacks, device impersonation, and physical tampering.