Broadway tuner “Avenue Q” will shutter in the fall after a run of six years.

Comedy, in which a cast of humans and puppets play twentysomethings struggling to find their way in New York City, was one of the first of a new generation of small-scale offerings that carved out a stable foothold on a Rialto landscape more often associated with splashier fare.

Broadway production has grossed almost $120 million so far, and, according to reps for the show, returned $23.5 million to its investors.

The last several months of its Main Stem run have seen sales diminish, with weekly box office sometimes dipping below the $200,000 mark. Both the production’s low running costs and its berth at one of Broadway’s smaller venues, the John Golden Theater, helped extend its longevity.

The show became the epitome of an underdog legit success when the musical beat out big-budget competitor “Wicked” for the top tuner Tony in 2004.

Also picking up trophies for score (for composer-lyricists Robert Lopez and Jeff Marx) and book (for Jeff Whitty), “Avenue Q” was notable as well for a tongue-in-cheek, unusually aggressive awards campaign seemingly modeled after the high-profile pushes of Oscar contenders. (A year later, the administrators of the Tony Awards issued regulations limiting such campaigns.)

The show went on to stir up controversy just after the Tonys, when a seemingly imminent road incarnation was nixed in favor of a short-lived 2005 stint in Vegas. (A tour eventually went out, recently wrapping up two years on the road.)

In Gotham, the tuner became one of the more successful Broadway transfers of a show that originated at an Off Broadway nonprofit. “Avenue Q” preemed in a co-production by the Vineyard Theater and the New Group, playing at the Vineyard in spring 2003. The show opened at the Golden that July.

Similarly quirky or edgy musicals from Gotham nonprofits — including “Spring Awakening” and “The 25th Annual Putnam County Spelling Bee”– have subsequently gone on to successful Rialto runs, although none have outlasted “Avenue Q.”

The show also is playing in London, in a West End production that opened at the Noel Coward Theater in 2006 and recently jumped to the Gielgud.

On Broadway, “Avenue Q” will stick around through Labor Day to benefit from tourist-boosted summer biz. When the tuner closes Sept. 13, it will have played 2,534 perfs and 22 previews.

Helmed by Jason Moore (“Shrek the Musical”), “Avenue Q” is produced by Kevin McCollum, Robyn Goodman, Jeffrey Seller, the Vineyard and the New Group.