In the complex world, uncertainty and fuzziness exist in many applications. Zadeh initially proposed the concept of fuzzy sets for capturing the uncertainty and fuzziness of information. Since its establishment, many extensions of fuzzy sets have been proposed for better expressing complex information, such as intuitionistic fuzzy sets, picture fuzzy sets, q-rung orthopair fuzzy sets, and neutrosophic sets. Many research results concerning their decision-making theories and methods have been obtained by researchers and scholars. However, there are few research results that report the applications of fuzzy sets and their extensions (FSTEs) in engineering.

The aim of this Special Issue is to solicit high-quality research that reports the emerging applications of fuzzy sets and their extensions in engineering, such as control systems, artificial intelligence (AI), and Internet of Things (IoT). Original research and review articles are welcome.

Potential topics include but are not limited to the following:

• IoT and cloud services ranking models based on FSTEs
• Additive manufacturing process selection based on FSTEs
• Medical decision making based on FSTEs
• Controller network based on FSTEs
• Transport systems based on FSTEs
• Failure mode and effect analysis based on FSTEs