A container holder for vehicles includes an aperture that can be automatically adjusted in size to accommodate differently sized containers. In one embodiment, a container holder includes a resilient sidewall with overlapping ends and locking mechanism for adjustably locking the sidewall into a selectable diameter. In another embodiment, a container holder includes a base having a first aperture, a movable plate pivotally mounted to the base having a second aperture aligned with the first aperture, and a bias spring biasing the plate toward an angled position whereby the projected area of the second aperture is reduced so that the plate moves and container holder automatically adapts in size to a container placed in the first and second apertures.