有机化学是研究有机化合物及有机物质的结构、性质、反应的学科，是化学中极重要的一个分支。有机化学研究的对象是以不同形式包含碳原子的物质，又称为碳化合物的化学。

有关有机化合物或有机物质结构的研究包括用光谱、核磁共振、红外光谱、紫外光谱、质谱或其他物理或化学方式来确认其组成的元素、组成方式、实验式及化学式。有关性质的研究包括其物理性质及化学性质，也需评估其化学反应性，目的是要了解有机物质在其纯物质形式（若是可能的话），以及在溶液中或是混合物中的性质。有机反应的研究包括有机物质的制备（可能是有机合成或是其他方式），以及其化学反应，可能是在实验室中的，或是In silico（经由电脑仿真的）。

Organic chemistry is a chemistry subdiscipline involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms. Study of structure includes many physical and chemical methods to determine the chemical composition and the chemical constitution of organic compounds and materials. Study of properties includes both physical properties and chemical properties, and uses similar methods as well as methods to evaluate chemical reactivity, with the aim to understand the behavior of the organic matter in its pure form (when possible), but also in solutions, mixtures, and fabricated forms. The study of organic reactions includes probing their scope through use in preparation of target compounds (e.g., natural products, drugs, polymers, etc.) by chemical synthesis, as well as the focused study of the reactivities of individual organic molecules, both in the laboratory and via theoretical (in silico) study.