jats:sec<jats:label />jats:pLightweight cellular materials are engineered to enhance performance attributes such as energy absorption, specific stiffness, negative Poisson's ratio, negative thermal expansion coefficient, etc. However, self‐sensing functionality of such architected materials is seldom explored. Herein, a combined experimental and numerical study on additive manufacturing (AM)‐enabled self‐sensing cellular composites processed via fused filament fabrication, utilizing in‐house engineered multiwall carbon nanotube (MWCNT)/polypropylene random copolymer (PPR) filament feedstocks, is reported. The tunable self‐sensing and enhanced mechanical performance of PPR/MWCNT lattices are experimentally demonstrated by varying their architectural parameters in addition to the MWCNT content. The lattices reveal strain and damage sensitivity gauge factors of 12 and 1.2, respectively, comparable to bulk materials’ commercial gauge factors. Furthermore, self‐sensing lattices exhibit 200%, 155%, 153%, and 137% increase in stiffness, energy absorption capacity (as high as 4.7 MJ mjats:sup−3</jats:sup>), specific energy absorption (20.5 J gjats:sup−1</jats:sup>), and energy absorption efficiency (90%), respectively, compared with their non‐reinforced counterparts. The tunable multifunctional performance of AM‐enabled cellular composites demonstrated here provides guidelines for the design and development of composite lattices with advantaged structural and functional properties for an array of applications such as patient‐specific biomedical devices capable of measuring comfort in prosthetics.</jats:p></jats:sec>