绿色萤光蛋白(Green fluorescent protein，简称GFP)，是一个由238个氨基酸残基组成的蛋白，在蓝色到紫外线波长范围的光线激发下，会发出绿色萤光。虽然许多其他海洋生物也有类似的绿色荧光蛋白，绿色荧光蛋白（GFP）传统是指首先从维多利亚多管发光水母中分离的蛋白质。这种蛋白质最早是由下村修等人在1962年在维多利亚多管发光水母中发现。这个发光的过程中还需要冷光蛋白质水母素的帮助，且这个冷光蛋白质与钙离子(Ca)可产生交互作用。

由维多利亚多管发光水母中发现的野生型绿色萤光蛋白，395nm和475nm分别是最大和次大的激发波长，它的发射波长的峰点是在509nm，在可见光绿光的范围下是较弱的位置。绿色荧光蛋白的荧光量子产率（QY）为0.79。由海肾(sea pansy)所得的绿色萤光蛋白，仅有在498nm有一个较高的激发峰点。

The green fluorescent protein (GFP) is a protein composed of 238 amino acid residues (26.9 kDa) that exhibits bright green fluorescence when exposed to light in the blue to ultraviolet range. Although many other marine organisms have similar green fluorescent proteins, GFP traditionally refers to the protein first isolated from the jellyfish Aequorea victoria. The GFP from A. victoria has a major excitation peak at a wavelength of 395 nm and a minor one at 475 nm. Its emission peak is at 509 nm, which is in the lower green portion of the visible spectrum. The fluorescence quantum yield (QY) of GFP is 0.79. The GFP from the sea pansy (Renilla reniformis) has a single major excitation peak at 498 nm.