The objective of this Special Issue is to highlight applications of legacy and next-generation sensors along with advanced analytic techniques for machinery monitoring. The Issue presents novel sensor concepts, designs, and applications that support advanced decision-making approaches by incorporating sensors, real-time decision-making methods, and operational policies. Industrial sensors play a critical role in the advancement of smart manufacturing with growing demand for integrated smart systems in which most sensors, designs, and operations are digitalized to enhance reliability, efficiency, and data-driven insights. This Special Issue addresses current limitations and key advancements in sensors for machinery condition monitoring, diagnostics, prognostics, and maintenance, while also considering legacy operations and emerging system types.