The parliament unanimously approved "the deployment of members of the Egyptian armed forces on combat missions outside Egypt's borders to defend Egyptian national security ... against criminal armed militias and foreign terrorist elements", it said in a statement, Aljazeera reported.
The decision comes after President Abdel-Fattah al-Sisi warned Cairo could intervene in neighboring Libya across Egypt's western border.
The move could bring Egypt and Turkey, both US allies that support rival sides in Libya’s chaotic war, into direct confrontation.
Forces of Libya’s UN-backed Government of National Accord are moving closer to the strategic city of Sirte, which Sisi described as Cairo’s red line.
Libya has been beset by chaos since the overthrow and killing of its long-serving ruler Muammar Gaddafi following a NATO operation in 2011. The conflict has escalated into a regional proxy war fueled by foreign powers pouring weapons and mercenaries into the country.
Tensions escalated further last year after the Libyan National Army under renegade general Khalifa Haftar moved toward Tripoli to seize the city.
The UN-backed government in Tripoli has the support of Turkey, while the LNA based in Benghazi is supported by Russia, Egypt and the United Arab Emirates.
A big escalation in Libya could risk igniting a direct conflict among the foreign powers that have poured in weapons and fighters in violation of an arms embargo.