Hydrogen bond cooperativity describes how the formation or strength of one hydrogen bond affects neighboring hydrogen bonds within a network. This mutual influence is non-additive and results in changes to structural, energetic, and spectroscopic properties that cannot be explained by considering individual hydrogen bonds in isolation. Cooperativity plays a significant role in the stability, folding, and function of biological macromolecules, supramolecular assemblies, and coordination complexes. These effects are important in diverse chemical systems, such as protein structures, nucleic acids, and coordination compounds. Most common experimental approaches for studying hydrogen bond cooperativity include vibrational spectroscopy (IR, Raman) and NMR, which provide quantitative measures of network effects. Quantum-chemical calculations, particularly density functional theory and correlated wavefunction methods, allow detailed analysis of the electronic origins of cooperativity. Molecular dynamics simulations provide insights into the dynamic behavior of hydrogen-bonded networks in various environments. This review summarizes current approaches for identifying and quantifying hydrogen bond cooperativity. The focus is on methods that characterize network effects through thermodynamic, structural, and spectroscopic criteria, supported by computational models. Persistent challenges include the separation of cooperativity from other effects and the accurate modeling of solvent influence and many-body contributions with moderate computational costs. Understanding hydrogen bond cooperativity is crucial for the rational design of biomolecules, catalysts, and functional materials in coordination chemistry.