Her comments came amid a report that Ivanka and Donald Jr. were in a "cold war" in which both have vied for influence over the family "dynasty."
"There's stories about them being a dynasty -- that after Trump is gone, then the next idiot and then the next idiot and then the next idiot," she said.
She added: "This family is filled with mediocrities. Trump, to his credit, is a hideous, charismatic con man -- that has a little potential for something. These other ones have nothing."
While co-host Meghan McCain touted Trump Jr.'s popularity in the U.S., she criticized Ivanka for not living up to the "hype" surrounding her.
"It was fascinating that he, on the campaign trail, is one of the biggest fundraisers for the [Republican National Committee]," McCain said of Trump Jr., "that apparently in red America, he's like a folk hero and that he actually has turned into the person that's been basically the most beneficial for the administration when Ivanka, I still don't know what she does all day, hasn't necessarily lived up to the hype."
After co-host Abby Huntsman said she felt sorry for Trump's kids, Behar mockingly said, "Oh, boo hoo hoo." Huntsman added that she once spent "the whole day" with Ivanka and got the impression that the president's daughter disagreed with her father on "almost everything."
"When I interviewed Ivanka, I could see it in her face ... that she wanted to tell me something that she couldn't," Huntsman said, before claiming that she faced a tough choice in her relationship with her father.
Behar suggested it was ridiculous to see Ivanka as being in a tough spot, claiming that she should make the decision to oppose her father and "save the United States."
Co-host Sunny Hostin questioned why Ivanka was even in the White House, noting that the idea of a political dynasty was "dated."
"Why is Donald Trump Jr. thinking that he can run for office?" Hostin asked. "Just because their father is the president, doesn't make them heir apparent to anything. They need to work for everything that they have."