This study presents the development of thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose, graphene oxide, and sepiolite nanorods. The foams are produced by freeze-casting suspensions of these materials, resulting in ultralight, highly porous structures with excellent combustion resistance. The thermal conductivity of the foams is significantly lower than traditional insulation materials like expanded polystyrene (EPS), reaching 15 mW m\(^{-1}\) K\(^{-1}\). The foams retain more than half of their initial strength at 30 °C and 85% relative humidity. The anisotropic properties of the foams, with high axial specific Young's modulus and low radial thermal conductivity, make them suitable for applications such as thermal insulation in walls. The addition of graphene oxide and sepiolite enhances the mechanical strength and fire retardancy, with a limiting oxygen index (LOI) of 34 and only occasional ignition in cone calorimetry tests. The study highlights the potential of nanoscale engineering using renewable resources to produce high-performance thermal insulating materials.This study presents the development of thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose, graphene oxide, and sepiolite nanorods. The foams are produced by freeze-casting suspensions of these materials, resulting in ultralight, highly porous structures with excellent combustion resistance. The thermal conductivity of the foams is significantly lower than traditional insulation materials like expanded polystyrene (EPS), reaching 15 mW m\(^{-1}\) K\(^{-1}\). The foams retain more than half of their initial strength at 30 °C and 85% relative humidity. The anisotropic properties of the foams, with high axial specific Young's modulus and low radial thermal conductivity, make them suitable for applications such as thermal insulation in walls. The addition of graphene oxide and sepiolite enhances the mechanical strength and fire retardancy, with a limiting oxygen index (LOI) of 34 and only occasional ignition in cone calorimetry tests. The study highlights the potential of nanoscale engineering using renewable resources to produce high-performance thermal insulating materials.