"No company subject to CCP (Chinese Communist Party) dictates should have the power to accumulate such extensive data on the American people or curate content to nearly a third of our population," Bennet wrote in the letter to Alphabet Chief Executive Sundar Pichai and Apple CEO Tim Cook.
"Given these risks, I urge you to remove TikTok from your respective app stores immediately," he wrote.
The app, which Congress has already banned from federal government devices, has come under increasing criticism because of concern that China's government could use it to harvest data on Americans or advance Chinese interests.
Prior to Bennet's letter, Republicans have largely led the charge on TikTok and national security concerns.
In the US House of Representatives, which is now in Republican hands, the Foreign Affairs Committee plans to hold a vote this month on a bill aimed at blocking TikTok's use in the United States, the committee has confirmed.
In 2020, then-President Donald Trump attempted to block new users from downloading TikTok and ban other transactions that would have effectively prevented TikTok's use in the United States, but the move was rebuffed by the courts.
For its part, the company says China's government cannot access the personal data of US citizens or manipulate the app's content.
TikTok Chief Executive Shou Zi Chew is due to appear before the US House Energy and Commerce Committee in March.