The generalized theta graph Θ_{s1, …, sk} consists of a pair of endvertices joined by k internally disjoint paths of lengths s₁, …, s_k1. We prove that the roots of the chromatic polynomial π(Θ_{s1, …, sk}, z) of a k-ary generalized theta graph all lie in the disc z−1[1+o(1)] k/log k, uniformly in the path lengths s_i. Moreover, we prove that Θ_2, …, 2K_2, k indeed has a chromatic root of modulus [1+o(1)] k/log k. Finally, for k8 we prove that the generalized theta graph with a chromatic root that maximizes z−1 is the one with all path lengths equal to 2; we conjecture that this holds for all k.