An expectiminimax tree is a specialized variation of a minimax tree for use in artificial intelligence systems which play games of chance.

In the traditional minimax method, the levels of the tree alternate from max to min until the depth limit of the tree has been reached. However, in an expectiminimax tree, the levels of max and min are interleaved with "chance" nodes, which, instead of taking the max or min of the utility values of their children, take a weighted average, with the weight being the probability that that child is reached.