Given a finite alphabet Σ and a right-infinite word w over Σ, we define the Lie complexity function Lw : N → N, whose value at n is the number of conjugacy classes (under cyclic shift) of length-n factors x of w with the property that every element of the conjugacy class appears in w.We show that the Lie complexity function is uniformly bounded for words with linear factor complexity, and as a result we show that words of linear factor complexity have at most finitely many primitive factors y with the property that y n is again a factor for every n.We then look at automatic sequences and show that the Lie complexity function of a k-automatic sequence is again k-automatic.