The House committee plans several hearings, depositions and interviews with competitors over the next 18 months. In addition, the Justice Department and the Federal Trade Commission, the two top antitrust agencies, recently divided antitrust oversight over Apple, Amazon, Facebook and Google.

Numerous state attorneys general are also preparing inquiries into the biggest tech companies. Many of them are meeting with F.T.C. officials on Wednesday to talk about antitrust oversight.

The close reviews could lead to years of troubles for the companies, through lawsuits or new laws. European regulators have already taken a tough stance against the companies, investigating how they handle user data, police speech and limit competition.

Mr. Cicilline, who is leading the Judiciary Committee’s investigation, said he would explore a variety of issues. He said the committee would look into whether the dominant social network, Facebook, had harmed consumers with its handling of data, for example. He said it also planned to look into whether Amazon had hurt smaller retailers.

The House investigation will look into whether the Justice Department and F.T.C. have adequately enforced antitrust laws. Mr. Cicilline said Facebook’s acquisitions of WhatsApp in 2014, for instance, now appeared anticompetitive, even though federal regulators had approved it.