Executives of Google Inc. will be called to testify before at least two congressional committees this fall to answer questions about its $3.1 billion buyout of DoubleClick Inc. and its impact on online advertising and consumer privacy.

The Senate Judiciary Committee’s antitrust panel plans to hold a hearing in September focusing on the consolidation sweeping the online-advertising market. A House Commerce subcommittee on consumer protection is also planning a hearing, which will reportedly focus on consumer privacy concerns raised by the deal.