A mounting system for securing a container to a bed of a vehicle or other installation location includes a sidewall mounting bracket for mounting to a first sidewall of the bed. An arm body has a length dimension that is adjustable. A first joint pivotally attaches a first end of the arm body to the sidewall mounting bracket for pivotal movement relative to the first sidewall of the bed when the sidewall mounting bracket is mounted to the first sidewall of the bed. A second joint for attaching a second end of the arm body to the container.