Conventional manufacturing systems are shifting toward smart manufacturing where a wide range of devices are connected to the Internet, thanks to advances in Internet of Things (IoT) technology. The high connectivity of such devices introduces security risks because malicious nodes may attempt to compromise or tamper with data generated by the devices. This in turn highlights the security and data trust challenges in smart manufacturing. In this chapter, we discuss blockchain as a solution to address the outlined challenges. We study the state-of-the-art solutions proposed in the literature to enhance security and establish trust in manufacturing. Next, we introduce a blockchain-based framework to secure smart manufacturing by analyzing the data logs produced by the devices. Ultimately, we envision a blockchain-based framework to enforce trustworthiness in Digital Twins (DTs) that mirror every facet of the industrial processes to help achieve predictive maintenance.