Subgrid-scale interactions between turbulence and radiation are potentially important for accurately simulating marine low clouds in climate models. To better understand the impact of these interactions, the Weather Research and Forecasting model is configured for large eddy simulation to study the stratocumulus to trade cumulus (Sc-to-Cu) transition. Using the Global Energy and Water Cycle Experiment Atmospheric System Studies composite Lagrangian transition case and the Atlantic Trade Wind Experiment case, it is shown that the lack of subgrid-scale turbulence-radiation interaction, as is the case in current generation climate models, accelerates the Sc-to-Cu transition. Our analysis suggests that subgrid-scale turbulence-radiation interactions in cloud-topped boundary layers contribute to stronger production of temperature variance, which in turn leads to stronger buoyancy production of turbulent kinetic energy and helps to maintain the Sc cover.