The enormous benefits of Internet of Things (IoT) technology have driven its deployment in various applications. Additionally, the development of quantum computers has directed attention towards lattice-based cryptography. Consequently, the computational capabilities of quantum computers pose a threat to the security of the existing IoT signature mechanisms. Quantum computers are proficient at unraveling the complexity bound of computationally hard problems like the integer factorization problem (IFP) and the discrete logarithm problem (DLP). As a result, security is an essential requirement for the IoT communication network against quantum attacks. The amalgamation of certificateless public key cryptosystems (CL-PKC) and lattice-based cryptography (LBC) is one of the solution for alleviating these security menaces. Lucidly, CL-PKC prevents key escrow issues and key management problems; LBC prevents quantum attacks. The Shortest Integer Solution (SIS) problem, which the NTRU lattices offer, serves as the basis for this paper’s introduction of a certificateless signature mechanism for IoT environments. By adopting the Random Oracle Model, we demonstrated the security of the suggested mechanism against Type 1 and Type 2 attackers. Furthermore, security analysis and performance evaluation demonstrate robust communication, as evidenced by metrics such as the computational cost of CL-Sign and CL-Verify phases at 536 μs , 376.81 μs and communication cost of KGC at 418 bits, CL-Sign at 532 bits and CL-Verify at 446 bits. Also, we calculate the cost of single-message signature generation and verification on an IoT device. These results show that the suggested mechanism’s security and computational efficiency are more reliable, and efficient than other relevant competing frameworks.