Examples herein relate to intrusion switch. In particular, implementations herein relate to a computer system including a housing enclosing at least one electronic component therein. The housing includes a base and a removable cover. The cover is movable between engaged and disengaged positions relative to the base and extends over at least a portion of the base and is secured to the base in the engaged position. The cover is removable from the base when the cover is in the disengaged position. The computer system further includes an intrusion switch configured to detect access to an interior of the computer system. A portion of the cover extends through a slot in one of the sidewalls of the base and contacts the intrusion switch when the cover is in the engaged position. Contact between the cover and the intrusion switch is released when the cover is in the disengaged position such that the intrusion switch can detect when the cover is moved to the disengaged position.