尼斯模型（英语：Nice model，(英语发音：/ˈniːs/ neess）是一个太阳系动力演化理论。该理论以提出地，蔚蓝海岸天文台所在的法国城市尼斯命名。该模型的提出是为了解释太阳系中的类木行星在原行星盘内气体消散很久之后从原本排列紧凑的位置迁移到今日位置的机制，这个模型和先前其他太阳系形成的模型并不相同。这个模型的太阳系动力学仿真是用来解释太阳系内许多事件，其中包含了内太阳系的后期重轰炸期、奥尔特云的形成、太阳系小天体的分布，例如柯伊伯带，木星与海王星的特洛伊天体，以及大量被海王星重力影响的共振海王星外天体。这个模型因为许多对太阳系天体观测的结果符合其预测而获得成功，并且是近年最被广泛接受的太阳系早期演化模型；虽然它并没有被行星科学家普遍接受。该模型其中一个限制就是外行星的卫星和柯伊伯带（参见下文）。

The Nice (/ˈniːs/) model is a scenario for the dynamical evolution of the Solar System. It is named for the location of the Observatoire de la Côte d'Azur, where it was initially developed, in Nice, France. It proposes the migration of the giant planets from an initial compact configuration into their present positions, long after the dissipation of the initial protoplanetary gas disk. In this way, it differs from earlier models of the Solar System's formation. This planetary migration is used in dynamical simulations of the Solar System to explain historical events including the Late Heavy Bombardment of the inner Solar System, the formation of the Oort cloud, and the existence of populations of small Solar System bodies including the Kuiper belt, the Neptune and Jupiter trojans, and the numerous resonant trans-Neptunian objects dominated by Neptune. Its success at reproducing many of the observed features of the Solar System means that it is widely accepted as the current most realistic model of the Solar System's early evolution, although it is not universally favoured among planetary scientists. One of its limitations that it does not reproduce the outer-system satellites and the Kuiper belt (see below).