Shares of the San Francisco company at last check were climbing 4.2% to $47.85.
Analyst Lloyd Walmsley set a share price target of $56, up from $36.
"Twitter is well positioned to benefit from a big event landscape in 2021, expansion into more performance advertising on the back of its ad server rebuild and new [mobile application promotion] product, and an eventual high-margin subscription product," the analyst said in a note to clients.
Twitter user growth has benefited from the coronavirus pandemic, Walmsley said. But its focus on brand advertising - the weakest segment of the ad market - has resulted in poor revenue performance, holding back the shares from an otherwise good story in 2021.
"We are starting to pick up signs of a resurgence in U.S. national brand advertising in general, and specifically on Twitter in the third quarter," the analyst said.
Due to the positive feedback in the ad channel, Walmsley advised "taking advantage of the opportunity to build a position now before a stronger ad recovery takes hold and we get into the period of 2021 excitement."
Looking to 2021, Walmsley said, he sees "a number of tent-pole events for robust growth in engagement and revenue on Twitter, including the NFL, MLB and NBA being able to to play full seasons, as well as the full return of college football as a driver for growth."
"Internationally," he said, "we see the Olympics, the EuroCup and World Baseball Classic as strong global drivers for user engagement, particularly in Japan, which is a strong market for Twitter."
Walmsley also said he saw a strong release schedule for movies and TV show, "which we see as coming back after halting in 2020."