在化学中，质子化是原子、分子或离子获得质子（H）的过程。　 简单的可以理解为和质子化合， 即结合一个质子，一般都是该物质有孤对电子，所以可以通过配位键结合一个质子。如H₂O变成H₃O，NH₃变成NH₄等等。 质子化的逆过程是去质子化。

质子化可能是最基本的化学反应，是很多化学计量和催化过程中的一步。一些多元离子和原子可以进行多次质子化，例如很多生物高分子。

基底经过质子化后，其中每一种粒子的质量和电荷都增加了一个单位。分子质子化或去质子化后，很多化学性质都发生了改变，不仅限于电荷和质量，如亲水性、还原势、光学特性等。在特定的分析步骤中，如电喷雾质谱，质子化是必需的一步。

In chemistry, protonation is the addition of a proton (H) to an atom, molecule, or ion, forming the conjugate acid. Some examples include

Protonation is a fundamental chemical reaction and is a step in many stoichiometric and catalytic processes. Some ions and molecules can undergo more than one protonation and are labeled polybasic, which is true of many biological macromolecules. Protonation and deprotonation occur in most acid-base reactions; they are the core of most acid-base reaction theories. A Bronsted-Lowry acid is defined as a chemical substance that protonates another substance. Upon protonating a substrate, the mass and the charge of the species each increase by one unit. Protonating or deprotonating a molecule or ion alters many chemical properties beyond the change in the charge and mass: hydrophilicity, reduction potential, optical properties, among others. Protonation is also an essential step in certain analytical procedures such as electrospray mass spectrometry.