A type 3 stealth assault was a military tactic employed by the Hierarchy of the Delta Quadrant.

This tactic involved cloaked Assault class vessels approaching their target and decloaking once in its immediate vicinity. A warning shot would then be fired across the target's bow, and then a message would be sent with demands for materials and technology. Failure of the target to comply with the demands would result in its destruction.

In 2376, the Hierarchy initially chose to use a type-3 stealth assault against the USS Voyager. That decision was based on the false belief from The Doctor's daydreaming algorithm that he was in command and would use his photonic cannon against them, which they had viewed destroying a Borg sphere in one volley. Upon realizing that Voyager was undamaged from this fictional attack, they changed their strategy to a type 4 assault. (VOY: "Tinker Tenor Doctor Spy")