A lobbying group for some of the nation’s biggest technology firms is urging new leaders at the Federal Trade Commission to resist growing pressure for changes to the agency’s decades-old antitrust enforcement approach.

The Computer & Communications Industry Association, whose membership includes Alphabet Inc.’s Google, Facebook Inc., and Amazon.com Inc., launched a new initiative this year to counter attacks on the existing U.S. antitrust framework. The group has lobbied Congress on the issue and is now turning its attention to the FTC, which is planning this week to kick off a series of competition and consumer protection policy hearings.

The...