A cable management device is applicable to a cable management assembly. The cable management device includes a first component and a second component. The first component includes a wall. A cable management space is defined by the first component and the second component. The second component is configured to be opened or closed relative to the first component. The second component includes two portions. When the second component is closed relative to the first component, the wall of the first component is engaged between the two portions of the second component.