趋光性（英语：Phototaxis）是一种生物对光靠近或者远离的趋性。

在有趋光性的生物中，拥有正趋光性的会靠近光源，而有负趋光性的会躲避光线的刺激。这样对于植物等自养生物来说十分重要，因为趋光性可以帮助植物获得更多阳光以进行光合作用。

Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite.