The Democratic-led House Oversight Committee on Wednesday approved the subpoena after a contentious hearing over whether Conway broke the law when she talked politics during media appearances.
"The American people demand that our public officials follow the law and be held accountable for their actions," Oversight panel Chairman Elijah Cummings, D-Md., said. "Through this resolution, the committee demands answers and requires Ms. Conway to provide those answers under oath."
The vote could lead to a contempt of Congress citation if Conway refuses to appear.
Conway serves as counselor to President Trump and is a frequent guest on television shows, where she advocates for the president's agenda and takes jabs at his critics, namely Democrats and their agenda.