Abstract: In modern digital governance, ensuring secure, transparent, and tamper-proof elections remains a critical challenge. Traditional voting systems, whether paper-based or electronic, suffer from issues such as centralized control, lack of transparency, and vulnerability to tampering. This paper proposes a Blockchain-Based Decentralized E-Voting System that utilizes Ethereum smart contracts, MetaMask authentication, and a Flutter-based frontend to provide a secure and transparent voting mechanism. Each vote is recorded as an immutable blockchain transaction, ensuring integrity, verifiability, and prevention of double voting. The system eliminates the need for third-party intervention and enables real-time result verification. Experimental results demonstrate improved security, reliability, and scalability, making the system suitable for modern digital election processes. Keywords: Blockchain, E-Voting, Smart Contracts, Ethereum, MetaMask, Decentralization, Web3