五夸克粒子是一种次原子粒子，属于奇异强子。五夸克粒子有五个夸克。更详细地说，是四个夸克和一个反夸克（表示他的重子数为1）。虽然物理学者预言五夸克粒子存在已很多年了，五夸克态显然很不容易被发现。有些物理学者甚至提议，某种未知自然定律阻止五夸克粒子的出现。

2000年代，曾经有几个实验报告发现五夸克态的存在，但对于这些实验所获得的数据做重新分析，再加上对于后来完成的实验做分析，所得到的结论是，这些先前得到的结果都是统计效应，而不是真实的共振。2015年7月13日，欧洲核子研究组织的LHCb实验团队报告，在底Λ粒子 （Λ0
b）的衰变反应中，发现了五夸克态，但这结果尚未经过同行评议。

A pentaquark is a subatomic particle consisting of four quarks and one antiquark bound together.

As quarks have a baryon number of +⁄₃, and antiquarks of −⁄₃, the pentaquark would have a total baryon number of 1, and thus would be a baryon. Further, because it has five quarks instead of the usual three found in regular baryons (aka 'triquarks'), it would be classified as an exotic baryon. The name pentaquark was coined by Claude Gignoux et al. and Harry J. Lipkin in 1987; however, the possibility of five-quark particles was identified as early as 1964 when Murray Gell-Mann first postulated the existence of quarks. Although predicted for decades, pentaquarks have proved surprisingly difficult to discover and some physicists were beginning to suspect that an unknown law of nature prevented their production.