"There's been a lot of misinformation and even lies spread about SeaWorld, and we recognise that it has caused some people to have questions about the welfare of killer whales in human care," David D'Alessandro, chairman and interim chief executive officer, said in the statement.
"This long-term campaign will address those questions head on."
One video posted by SeaWorld rebuts claims by PETA that whales live shorter lives in captivity than in the wild.
"It's absolutely not true," Chris Dold, head veterinarian at the SeaWorld Park in Orlando, said in the clip.
The 2-minute, 44-second video takes viewers behind the scenes at the park, showing trainers and other animal-care workers monitoring the whales' weight and growth, and checking blood samples to catch illnesses early.
"I'm a veterinarian and just like doctors we veterinarians take an oath," said Dold, who narrated the segment. "I wouldn't work here if I wasn't able to give whales the first- class care they deserve."
SeaWorld is spending $10 million on print, TV and digital, according to Jill Kermes, a spokeswoman.
Print ads will run in national and local newspapers, including the Los Angeles Times and Sacramento Bee.
That's designed to reach California legislators who debated and then shelved a bill that would ban keeping whales in captivity.
"This is really about having an equal voice in the conversation," Kermes said in an interview.
PETA puts out almost a press release a week about SeaWorld, she said.
The company last week also named veteran entertainment executive Joel Manby to succeed former chief executive Jim Atchison, who stepped down in December. Manby takes over April 7.
The 2013 documentary film "Blackfish," about the death of a SeaWorld trainer, raised issues about the care of orcas in captivity and their use in entertainment.
The picture was shown in theatres and aired multiple times on CNN.
Kermes said CNN would be among the networks carrying the company's ads.
Since the film's release, entertainers such as Willie Nelson have cancelled park appearances and marketing partners including Southwest Airlines have ended their relationships.
In February, SeaWorld posted a fourth-quarter loss that exceeded analysts' estimates.
Visitors shrank to 4.4 million visitors from 4.5 million a year earlier, SeaWorld said. The company owns 11 theme parks in the United States.