AbstractMulticellular patterning of stem‐cell‐derived tissue models is commonly achieved via self‐organizing activities triggered by exogenous morphogenetic stimuli. However, such tissue models are prone to stochastic behavior, limiting the reproducibility of cellular composition and forming non‐physiological architectures. To enhance multicellular patterning in stem cell‐derived tissues, a method for creating complex tissue microenvironments endowed with programmable multimodal mechano‐chemical cues, including conjugated peptides, proteins, morphogens, and Young's moduli defined over a range of stiffnesses is developed. The ability of these cues to spatially guide tissue patterning processes, including mechanosensing and the biochemically driven differentiation of selected cell types, is demonstrated. By rationally designing niches, the authors engineered a bone‐fat assembly from stromal mesenchyme cells and regionalized germ layer tissues from pluripotent stem cells. Through defined niche‐material interactions, mechano‐chemically microstructured niches enable the spatial programming of tissue patterning processes. Mechano‐chemically microstructured cell niches thereby offer an entry point for enhancing the organization and composition of engineered tissues, potentiating structures that better recapitulate their native counterparts.