This article presents the design and additive manufacturing of multi-functional metamaterials using Invar 36 alloy, which integrate low coefficient of thermal expansion (CTE) and programmable Poisson’s ratio (PR). The metamaterials were fabricated using laser powder bed fusion (PBF-LB) and characterized for their densification, relative density, microstructures, CTE, and PR. The results show that the fabricated metamaterials exhibit uniform microstructures, resulting in isotropic low CTEs ranging from 1.79 to 1.85 ppm/°C. The designed metamaterials achieve PR tuning in the range of −0.54 to +0.58, confirming the PR programmability. The underlying mechanism is revealed that the variable θ1 dominates the transverse deformation behavior, achieving programmable PR. These metamaterials provide superior mechanical performances and a wider operating temperature range compared to polymer-based multi-functional metamaterials, offering broader application prospects.This article presents the design and additive manufacturing of multi-functional metamaterials using Invar 36 alloy, which integrate low coefficient of thermal expansion (CTE) and programmable Poisson’s ratio (PR). The metamaterials were fabricated using laser powder bed fusion (PBF-LB) and characterized for their densification, relative density, microstructures, CTE, and PR. The results show that the fabricated metamaterials exhibit uniform microstructures, resulting in isotropic low CTEs ranging from 1.79 to 1.85 ppm/°C. The designed metamaterials achieve PR tuning in the range of −0.54 to +0.58, confirming the PR programmability. The underlying mechanism is revealed that the variable θ1 dominates the transverse deformation behavior, achieving programmable PR. These metamaterials provide superior mechanical performances and a wider operating temperature range compared to polymer-based multi-functional metamaterials, offering broader application prospects.