Facebook is testing adverts in apps on the Oculus Quest and Quest 2 headsets.
The team at Facebook Reality Labs (FRL) has opened up about the move, and insisted this will help create "a self-sustaining platform".
In a lengthy blog post, Oculus said: "Last month, we announced that we’re starting to test ads in the Oculus mobile app to give developers a new way to showcase their VR applications.
"Today, we’re excited to share a look at the next phase of that exploration: a small test of in-headset ads.
"The experiment will begin with Blaston from Resolution Games and a couple other developers that will be rolling out over the coming weeks.
"Our primary focus at Facebook Reality Labs (FRL) is to bring more people into VR, advance the consumer experience, and make progress on our longer-term augmented reality initiatives.
"We’re also exploring new ways for developers to generate revenue—this is a key part of ensuring we’re creating a self-sustaining platform that can support a variety of business models that unlock new types of content and audiences.
"It also helps us continue to make innovative AR/VR hardware more accessible to more people."
Meanwhile, they confirmed the ads would be in line with Facebook's policies.
They added: "Ads are most effective when they’re high-quality and relevant—because of that, Oculus ads will follow Facebook’s advertising principles, the first of which is 'build for people first.'
"It’s also important that people can manage the ads they see, so we’re including controls to hide specific ads or hide ads from an advertiser completely.
"Users can also access more detailed Ad Preferences from any ad via our 'Why am I seeing this ad?' interface. As our tests progress, we’ll continue listening to feedback to improve the ads people see."
