BRUSSELS—Europe’s antitrust regulator took aim at Hollywood on Thursday, filing formal charges against six major U.S. film studios and pay-TV broadcaster Sky UK Ltd. over alleged illegal licensing agreements.

The European Union accused the companies of violating competition laws by using clauses that restrict access to Sky’s services outside Britain, in a move that could recast how pay-TV is sold and viewed in Europe.

The six studios are Walt Disney Co. ’s Disney, Comcast Corp. ’s NBCUniversal, Viacom Inc.’s Paramount Pictures, Sony Corp.’s Sony Pictures Entertainment Inc., 21 Century Fox’s Twentieth Century Fox and Time Warner Inc.’s Warner Bros. Entertainment.

The charges come amid a broader push by the European Union to eradicate barriers to a single market for digital services in the region. Regulators are focusing in particular on eliminating “geo-blocking,” where companies restrict access to films or other online content outside a particular licensed territory.

The European Commission, the bloc’s top antitrust authority, said Thursday that contracts between Sky and the six studios may have prevented Sky from offering its U.K. and Irish pay-TV services to EU consumers elsewhere. If that preliminary view is confirmed, “the clauses would constitute a serious violation of EU rules that prohibit anticompetitive agreements,” the EU said.