A quick adjustment assembly for a head or helmet mounted display. The quick adjustment assembly includes an adjustment plate assembly securely attachable to the head of a user via a helmet or head gear. An eye relief assembly is mountable on the adjustment plate assembly. The eye relief assembly includes a main frame for supporting at least one image source assembly (ISA). A pair of opposing pressure plate assemblies are supported by the main frame. Each pressure plate assembly includes an eye relief adjustment release element engageable by the user; and at least one pressure plate friction pad assembly operatively engageable with the adjustment plate assembly. The pressure plate friction pad assembly provides selectable positioning of the eye relief assembly along a plane of movement relative to the adjustment plate assembly allowing three-degrees of freedom movement along the plane of movement. The eye relief assembly preferably includes an interpupillary (IPD) adjustment assembly securely mounted thereon.