微管蛋白（英语：Tubulin）是一类含有多个成员的蛋白质家族。其最常见的成员是α-微管蛋白和β-微管蛋白，它们是组成微管的主要成分。微管由α-微管蛋白和β-微管蛋白所形成的二聚体为单位聚集而成。细胞内微管蛋白的聚集程度会影响微管的长度，并进一步影响细胞形态。微管蛋白的分子量约为55kDa，为弱酸性蛋白质，等电点在5.2至5.8之间。微管蛋白和同属于运动性蛋白的肌动蛋白和肌球蛋白在一级结构上有许多相似性。

很长一段时间，微管蛋白被认为只存在于真核生物中；但近来，一种原核细胞分裂蛋白FtsZ被发现在进化上与微管蛋白有联系。

Tubulin (tubul- + -in) in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytoskeleton. Microtubules function in many essential cellular processes, including mitosis. Tubulin-binding drugs kill cancerous cells by inhibiting microtubule dynamics, which are required for DNA segregation and therefore cell division.