The facile synthesis, solution-processability, and outstanding optoelectronic properties of emerging colloidal lead halide perovskite quantum dots (LHP QDs) makes them ideal candidates for scalable and inexpensive optoelectronic applications, including photovoltaic (PV) devices. The first demonstration of integrating CsPbI3 QDs into a conventional organic solar cell (OSC) involves embedding the LHP QDs in a donor-acceptor (PTB7-Th:PC71BM) bulk heterojunction. Optimizing the loading amount at 3 wt %, we demonstrate a power conversion efficiency of 10.8 %, which is a 35 % increase over control devices, and is a record amongst hybrid ternary OSCs. Detailed investigation into the mechanisms behind the performance enhancement shows that increased light absorption is not a factor, but that increased exciton separation in the acceptor phase and reduced recombination are responsible.