The Westside Theatre is an off-Broadway performance space at 407 West 43rd Street between Ninth and Tenth Avenues in the Hell's Kitchen neighborhood of Manhattan, New York City. The building houses two auditoriums: the Upstairs Theatre, which seats 270, and the Downstairs Theatre, which features a thrust stage and has a seating capacity of 249. The Westside Theater is currently hosting the musical Little Shop of Horrors. This is a horror comedy rock musical with music by Alan Menken and lyrics and a book by Howard Ashman. The story follows a hapless florist shop worker who raises a plant that feeds on human blood and flesh.

Formerly known as the Chelsea Theatre Center and the Westside Arts Theatre, the building was renovated in 1991.

The Romanesque Revival style building, designed by Henry Franklin Kilburn, was constructed in 1890 for the Second German Baptist Church, which it housed until the 1960s. The site was then occupied by various nightclubs until its establishment as a theatre in 1976.

A vast variety of historic, successful productions have been presented on these stages, including CAGNEY; TURN ME LOOSE; THE ABSOLUTE BRIGHTNESS OF LEONARD PELKEY; SATCHMO AT THE WALDORF; OLD JEWS TELLING JOKES; MY NAME IS ASHER LEV; LOVE LOSS AND WHAT I WORE; I LOVE YOU, YOU’RE PERFECT, NOW CHANGE (a record-breaking twelve-year run); TRUMBO; THE VAGINA MONOLOGUES; NIXON’S NIXON; FULL GALLOP; THE FOOD CHAIN; THE CRYPTOGRAM; SPIC-O-RAMA; and the inaugural productions, AND THE WORLD GOES ‘ROUND: THE SONGS OF KANDER AND EBB.

The Westside Theatre produced the Off-Broadway production of HEDWIG AND THE ANGRY INCH, which ran for two and a half years at the Jane Street Theatre (Westside’s downtown sister theatre), garnered the Outer Critics Circle award for Outstanding Off-Broadway musical of 1998, along with two OBIE awards.

The Westside Theatre also produced TRUMBO: RED WHITE AND BLACKLISTED, featuring a rotation of actors in the role of Dalton Trumbo, including Nathan Lane, Ed Harris, Richard Dreyfuss, Tim Robbins, Chris Cooper, Alec Baldwin, and Brian Dennehy. Other New York producing credits: Gretchen Law’s TURN ME LOOSE, John Leguizamo’s SPIC-O-RAMA, Doug McGrath’s POLITICAL ANIMAL, and the New York Musical Theatre Festival production of FEELING ELECTRIC, which later evolved into the Pulitzer Prize-winning musical NEXT TO NORMAL.