应用数学（英语：applied mathematics）是以应用为目的的明确的数学理论和方法的总称，研究如何应用数学知识到其他范畴（尤其是科学）的数学分支，可以说是纯数学的相反，应用纯数学中的结论扩展到物理学等其他科学中，应用数学的发展是以科学为依据，作为科学研究的后盾。包括微分方程、矢量分析、矩阵、拉普拉斯变换、傅里叶变换、复变分析、数值方法、概率论、数理统计、运筹学、博弈论、控制理论、组合数学、信息论等许多数学分支，也包括从各种应用领域中提出的数学问题的研究。而大部分应用数学是以作为物理分析的工具。计算数学有时也可视为应用数学的一部分。应用数学大部分的教学范畴都是以物理的模型为基础进行分析，当中或许搭配了各种数学工具，就为了更贴近物理的系统。

Applied mathematics is a branch of mathematics that deals with mathematical methods that find use in science, engineering, business, computer science, and industry. Thus, applied mathematics is a combination of mathematical science and specialized knowledge. The term "applied mathematics" also describes the professional specialty in which mathematicians work on practical problems by formulating and studying mathematical models. In the past, practical applications have motivated the development of mathematical theories, which then became the subject of study in pure mathematics where abstract concepts are studied for their own sake. The activity of applied mathematics is thus intimately connected with research in pure mathematics.