Because of its vectorial character, hydrogen bonding is one of the most important interactions that could be used to assemble molecular fragments into supramolecular structures. To explain the role of hydrogen bonds in supramolecular chemistry, we start our discussion from the fundamental points of view. In the first part of this article, the classification, physical properties, behavior, bond energy of hydrogen bonds, co-operative behavior, key and lock relationship, concept of resonance assisted hydrogen bonding phenomena (RAHB), Jorgensen-Schneider rules, and basic principles for the design of hydrogen bond arrays are discussed. In the second part, cases about the application of hydrogen bonding to molecular self-assembly and molecular folding are discussed.