Recent progress on highly tough and stretchable polymer networks has highlighted the potential of wearable electronic devices and structural biomaterials such as cartilage. For some given applications, a combination of desirable mechanical properties including stiffness, strength, toughness, damping, fatigue resistance, and self‐healing ability is required. However, integrating such a rigorous set of requirements imposes substantial complexity and difficulty in the design and fabrication of these polymer networks, and has rarely been realized. Here, we describe the construction of supramolecular polymer networks through an in situ copolymerization of acrylamide and functional monomers, which are dynamically complexed with the host molecule cucurbit8uril (CB8). High molecular weight, thus sufficient chain entanglement, combined with a small‐amount dynamic CB8‐mediated non‐covalent crosslinking (2.5 mol%), yields extremely stretchable and tough supramolecular polymer networks, exhibiting remarkable self‐healing capability at room temperature. These supramolecular polymer networks can be stretched more than 100× their original length and are able to lift objects 2000× their weight. The reversible association/dissociation of the host–guest complexes bestows the networks with remarkable energy dissipation capability, but also facile complete self‐healing at room temperature. In addition to their outstanding mechanical properties, the networks are ionically conductive and transparent. The CB8‐based supramolecular networks are synthetically accessible in large scale and exhibit outstanding mechanical properties. They could readily lead to the promising use as wearable and self‐healable electronic devices, sensors and structural biomaterials. Cucurbitnuril‐based supramolecular polymer networks are readily obtained through the in situ polymerization of guest‐functionalized monomers, upon completion with cucurbit8uril as supramolecular crosslinkers. The presence of CB8 host–guest complexes imparts the network with remarkable mechanical performances, including extreme stretchability, high toughness, energy dissipation, and fast room‐temperature self‐healing.