Investors are hoping a positive catalyst may come in the form of first-quarter earnings.
Doha's bourse slips 0.7 percent to 8,519 points, its lowest since March 14.
Heavyweight Qatar Telecom drops 4.4 percent and Qatar Navigation (Milaha) falls 5.8 percent, both trading post-dividend.
Abu Dhabi's benchmark declines 0.4 percent to 3,013 points, trimming 2013 points to 14.5 percent.
Dubai's measure is little changed at 1,830 points, hovering at a two-month low.
Elsewhere, Oman's bourse slips 0.2 percent to 5,975 points, and Kuwait's index is flat.