A large chunk of HBO's tally came from medieval fantasy "Game of Thrones," which received 32 nominations, the highest total for a drama series in a single year.
Limited series "Chernobyl" about the 1986 nuclear disaster hauled in 19.
Netflix ranked second with 117 nominations for shows including "When They See Us," a drama about the real-life men who became known as the Central Park Five, and comedy "Russian Doll."
TV networks and streaming services compete feverishly for Emmy nominations, which can help draw attention to programming and bring in new viewers or subscribers.
The prestige also helps attract top Hollywood talent at a time when media and technology companies are investing in their own alternatives to Netflix.
"Chernobyl" star Jared Harris, nominated for lead actor in a limited series, praised HBO for its "reputation for letting the creators do what they want to do."
"You don't hire a pilot and tell them how to fly a plane," he said in an interview.
The previous record for most nominations in a single year was set by HBO in 2015, when the network grabbed 131.
HBO had been a longtime Emmy darling and led the nominations for 17 straight years. But in 2018, Netflix knocked HBO to second place by landing 112 nominations to HBO's 108.
In the end, the networks tied with 23 Emmy wins each.
Winners of this year's awards will be announced Sept. 22 at a televised ceremony in Los Angeles.
HBO's other contenders include the comedies "Veep" and "Barry," drama "Succession" and variety series "Last Week Tonight with John Oliver."
Netflix's has two contenders for best drama, "Bodyguard" and "Ozark."
NBC, owned by Comcast Corp, led all broadcast networks with 58 nominations for shows such as family drama "This is Us," comedy "The Good Place" and sketch series "Saturday Night Live."
Amazon.com Inc ranked fourth with nominations for comedies "Fleabag," "The Marvelous Mrs. Maisel" and others.
In fifth place was CBS Corp.
The nominations included a best comedy series nod for "Schitt's Creek" on CBS-owned cable network Pop TV.
The channel recorded four nominations in total, the first in its history.