Understanding the effect of repulsive interaction between blocks on crystallization in block copolymers is beneficial for the design and development of sophisticated nanostructures. Dynamic Monte Carlo simulations were performed to reveal the crystallization mechanism of block copolymers containing one-dimensional nanofiller under different repulsive interaction strengths between crystallizable and noncrystallizable blocks. During crystallization, crystalline morphology is determined by the competition between segmental orientation perpendicular to microphase interfaces dominated by microphase separation and that along the direction of the long axis of the nanofiller controlled by interfacial interaction. As the repulsive interaction between different blocks is strengthened, the competition between microphase separation and interfacial interaction is intensified, eventually leading to an increase in crystallization rate and a degradation in crystalline morphology. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1516-1526