The Runhappy Stakes is a Grade III American Thoroughbred horse race for four years old or older at a distance of six furlongs on the dirt run annually in early May at Belmont Park in Elmont, New York. The event currently offers a purse of $175,000.

The event was inaugurated on 14 May 2014 as the Diablo Stakes and was won by the favorite Sensational Slam who defeated four other runners in a time of 1:09.07.^[1] The event was marred by the disqualification of the second place finisher Green Grotto who was placed third and Royal Currier installed in second for interference 1⁄8 mile from the finishing post. ^[2] The event was named after the versatile sprinter Diablo who won the 1991 Grade II True North Handicap and the 1992 Grade III Finger Lakes Budweiser Breeders' Cup. ^[3]

In 2018 the event was renamed to the Runhappy Stakes in honor of the 2015 US Champion Sprint Horse Runhappy.^[4]

The event was upgraded to Grade III in 2020^[5] but was not held due to the COVID-19 pandemic in the United States. Belmont Park ran a shortened meeting and the event was cancelled in favor of the rescheduled Carter Handicap being moved from Aqueduct Racetrack.^[6]

In 2024 the event was moved to Aqueduct Racetrack due to infield tunnel and redevelopment work at Belmont Park.^[7]

Speed record:

• 6 furlongs – 1:08.12 Firenze Fire (2019)

Margins:

• 4+3⁄4 lengths – Firenze Fire (2019)

Most wins:

• 2 – Stallwalkin' Dude (2015, 2017)
• 2 – Firenze Fire (2019, 2021)

Most wins by a jockey:

• 2 – Irad Ortiz Jr. (2019, 2021)

Most wins by a trainer:

• 2 – David Jacobson (2015, 2017)

Most wins by an owner:

• 2 – David Jacobson (2015, 2017)
• 2 – Mr. Amore Stable (2019, 2021)

List of American and Canadian Graded races