Twitter Inc. TWTR 1.30% has found its first partner for its push into round-the-clock streaming television: Bloomberg.

The social-media company is joining forces with the global financial news outlet to create a service that will stream news produced solely for Twitter 24 hours a day, seven days a week.

“It is going to be focused on the most important news for an intelligent audience around the globe and it’s going to be broader in focus than our existing network,” said Bloomberg Media’s chief executive officer, Justin Smith.

The partnership will be announced Monday at an event Bloomberg LP is holding for advertisers by company founder Michael Bloomberg and Twitter CEO Jack Dorsey.

The channel, which has yet to be named and is expected to begin operating this fall, won’t simply rebroadcast footage from Bloomberg’s existing television operation, but will be made up of live news reporting from the news outlet’s bureaus around the world, as well as a curated and verified mix of video posted on Twitter by the social-media platform’s users.

Twitter has already been streaming live programming for specific events. The company broadcast 800 hours of programming in the first quarter of 2017, up from 600 hours in the fourth quarter last year. But this would mark the first continuous video feed to be hosted on the platform.

Its most notable broadcast arrangement thus far was its deal with the National Football League to broadcast Thursday night games last season. Amazon has since acquired the rights to live stream football games this season. Twitter had previously partnered with Bloomberg for coverage of the presidential debates last year.

“We really think we can reach audiences that are not paying for TV and are watching television on the go and we think Bloomberg is the perfect partner for us to start with,” said Anthony Noto, Twitter’s chief financial and operating officer.

Both sides declined to discuss the financial aspects of the arrangement in detail, but said the service would be ad-supported and that Bloomberg would be entirely in control of programming the feed.

The effort comes at a turbulent time for Twitter, which this past week reported a decline in revenue for the first time since going public. It has struggled to find a successful formula for converting its sizeable user base into a fast-growing ad business.

Video has been a bright spot for Twitter recently, accounting for the largest portion of its ad revenue in the first quarter.

Yet the company faces fierce competition for video ad dollars. Google’s YouTube dominates the landscape, but Facebook Inc. has been growing rapidly in video, and Snapchat is aggressively targeting that same pot of money. All those companies are hoping to get advertisers to shift a significant portion of their spending from TV into online video.

Mr. Smith says the habit many Twitter users have of watching a live event on TV while simultaneously posting commentary on Twitter on their mobile phones made a strong case for attempting to meld the two.

“Viewers have already embraced a multistream experience with live events and marrying those experiences seemed like a very powerful thing to offer to consumers,” he said.

Write to Lukas I. Alpert at lukas.alpert@wsj.com