This review explores advancements in material extrusion-based 3D printing for sensor fabrication, focusing on fused filament fabrication (FFF) and direct ink writing (DIW). It examines the current state of knowledge in additive manufacturing of sensors using these techniques. The study uses a scoping review methodology, involving five stages: formulating the research question, database searches, establishing inclusion/exclusion criteria, data extraction, and discussion. A total of 68 sensors were analyzed, including strain, pressure, temperature, electrochemical, humidity, and pulse sensors. The FFF section discusses strain, accelerometer, acoustic emission, and electrochemical sensors, while the DIW section covers strain, pressure, temperature, electrochemical, humidity, antenna, and pulse sensors. Challenges in DIW and FFF-printed sensors are highlighted, including resolution, material compatibility, and performance issues. Conductive filaments and inks are used to fabricate sensors with properties like piezo-resistivity and piezoelectricity. These techniques allow for flexible, embedded sensor fabrication, enabling applications in soft robotics, wearable electronics, and prosthetics. Sensors can be printed extrinsically or embedded in objects, such as 3D-printed robotic hands with pressure-sensitive fingertips. FFF and DIW enable direct printing of conductive layers within flexible polymer matrices, reducing waste and enabling single-process fabrication of sensing elements and circuits. The review identifies key challenges and factors affecting sensor performance, providing insights for future research in material extrusion-based 3D printing of sensors.This review explores advancements in material extrusion-based 3D printing for sensor fabrication, focusing on fused filament fabrication (FFF) and direct ink writing (DIW). It examines the current state of knowledge in additive manufacturing of sensors using these techniques. The study uses a scoping review methodology, involving five stages: formulating the research question, database searches, establishing inclusion/exclusion criteria, data extraction, and discussion. A total of 68 sensors were analyzed, including strain, pressure, temperature, electrochemical, humidity, and pulse sensors. The FFF section discusses strain, accelerometer, acoustic emission, and electrochemical sensors, while the DIW section covers strain, pressure, temperature, electrochemical, humidity, antenna, and pulse sensors. Challenges in DIW and FFF-printed sensors are highlighted, including resolution, material compatibility, and performance issues. Conductive filaments and inks are used to fabricate sensors with properties like piezo-resistivity and piezoelectricity. These techniques allow for flexible, embedded sensor fabrication, enabling applications in soft robotics, wearable electronics, and prosthetics. Sensors can be printed extrinsically or embedded in objects, such as 3D-printed robotic hands with pressure-sensitive fingertips. FFF and DIW enable direct printing of conductive layers within flexible polymer matrices, reducing waste and enabling single-process fabrication of sensing elements and circuits. The review identifies key challenges and factors affecting sensor performance, providing insights for future research in material extrusion-based 3D printing of sensors.