Mozilla, the organization behind the Firefox Web browser, is putting its software on Internet-connected television sets, starting with Panasonic's.

Firefox OS becomes the latest system to power so-called smart TVs, which let viewers watch Internet video and interact with friends online on the big screen.

Mozilla's announcement and similar ones from LG, Roku and others at the International CES gadget show in Las Vegas will mean more smart TV choices for consumers—in contrast to the smartphone market, where Apple's iOS and Google's Android systems dominate.

But the slew of competing smart TV operating systems will make it difficult for services such as Hulu and Netflix to write apps.

On Monday, Mozilla and Panasonic said they will jointly develop and promote a version of Firefox OS for smart TVs.