Al-Wefaq, a Shiite-led party, was the largest bloc in Parliament with 18 members before mass protests began this winter. The chamber was elected last October.
The bloc submitted its resignation in February. The parliament accepted 11 MPs' resignation in March and the remaining seven Tuesday, the Gulf News reported.
The departure leaves the elected lower house with only 22 members as it heads for its summer recess starting Friday.
The 18 MPs are to be replaced in fall by-elections, with the first round Sept. 24 and runoffs Oct. 1 if needed.
Al-Wefaq boycotted the 2002 elections, the first after three decades of a suspended constitution, but was the leading party in 2006 and 2010. Sunni religious parties did well in 2006, but lots seats to independents in 2010.