分生组织指植物中具有分裂分化能力的细胞。这些细胞体积小，有着相对较大的细胞核，没有或者薄细胞壁。胞内被原生质充分填充。细胞排列紧密。

分生组织是植物中有特色的一个组织。植物在理论上有着潜在的永生能力，原因是其分生组织具有全潜能性。

分生组织按来源来分类，可划分为原分生组织（urmeristem），初生分生组织（primary meristem）和次生分生组织（secondary meristem）。按位置划分则有顶端分生组织（apical meristem），居间分生组织（intercalary meristem），侧生分生组织（lateral meristem）和拟分生组织（meristemoid）。.

A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place.

Meristematic cells give rise to various organs of the plant and keep the plant growing. The shoot apical meristem (SAM) gives rise to organs like the leaves and flowers, while the root apical meristem (RAM) provides the meristematic cells for the future root growth. SAM and RAM cells divide rapidly and are considered indeterminate, in that they do not possess any defined end status. In that sense, the meristematic cells are frequently compared to the stem cells in animals, which have an analogous behavior and function.