A mounting system (10) for securing a container (16) to a bed (18) of a vehicle or other installation location includes a sidewall mounting bracket (22) for mounting to a first sidewall (18a) of the bed (18). An arm body (30) has a length dimension that is adjustable. A first joint pivotally attaches a first end of the arm body (30) to the sidewall mounting bracket (22) for pivotal movement relative to the first sidewall (18a) of the bed (18) when the sidewall mounting bracket (22) is mounted to the first sidewall (18a) of the bed (18). A second joint for attaching a second end of the arm body (30) to the container (16).