This review discusses the integration of 3D-printed sensors into smart materials and structures, highlighting the advantages of 3D printing in terms of assembly processes, system complexity, and fabrication costs. The paper explores various additive manufacturing techniques, including fused filament fabrication (FFF), stereolithography (SLA), direct ink writing (DIW), and direct energy deposition (DED), and their applications in sensor development. It also delves into the sensing mechanisms of different types of sensors, such as piezoresistive, capacitive, and piezoelectric sensors, and their use in monitoring structural integrity and performance. The review further examines the challenges and future prospects of embedded sensors using 3D printing, emphasizing the potential for wireless and customizable sensors in various fields like medicine, space, industry, agriculture, and automobiles.This review discusses the integration of 3D-printed sensors into smart materials and structures, highlighting the advantages of 3D printing in terms of assembly processes, system complexity, and fabrication costs. The paper explores various additive manufacturing techniques, including fused filament fabrication (FFF), stereolithography (SLA), direct ink writing (DIW), and direct energy deposition (DED), and their applications in sensor development. It also delves into the sensing mechanisms of different types of sensors, such as piezoresistive, capacitive, and piezoelectric sensors, and their use in monitoring structural integrity and performance. The review further examines the challenges and future prospects of embedded sensors using 3D printing, emphasizing the potential for wireless and customizable sensors in various fields like medicine, space, industry, agriculture, and automobiles.