This article examines the effect of institutional investors' investment horizons on firms' innovation activities. We conjecture that the presence of long-term institutional investors mitigates managerial myopia, prompting firms to generate greater corporate innovation outputs. Using data on patents and patent citations for US firms, we find that institutions' investment horizons are positively related to the number of patents and patent citations. We also document that long-term (short-term) institutional ownership is positively (negatively) related to the innovation outputs. This article makes an additional contribution to the corporate innovation literature by addressing the positive role of long-term institutional investors.