Mendelssohn (foaled 17 May 2015) is a retired American Thoroughbred racehorse who won the 2017 Breeders' Cup Juvenile Turf and 2018 UAE Derby by over 18 lengths.

Mendelssohn is a bay colt bred in the United States by Clarkland Farm, owned by Fred and Nancy Mitchell.

[3][4] Leslie's Lady had been bred to Scat Daddy early in 2014 but lost that pregnancy due to the stress related to the illness of her 2013 foal, who died after only three months.

[6] The high price was the result of a bidding duel between Spendthrift Farm, which had raced Beholder, and Coolmore Stud, which was looking for a replacement for Scat Daddy.

The colt's registered ownership has changed several times, but he has always been owned by a combination of Coolmore partners Derrick Smith, Michael Tabor and Susan Magnier, or one of them individually.

Ryan Moore rode, and despite edging left inside the final furlong, Mendelssohn won comfortably by a length over Andesh.

He broke quickly and moved to the lead, then set a steady pace down the backstretch before starting to open a gap on the field around the far turn.

Mendelssohn eventually won by 18+1⁄2 lengths in a "jaw-dropping" performance while breaking the Meydan track record for 1900 metres (roughly 9.5 furlongs) by over a second.

[17] The performance earned a Beyer Speed Figure of 106 and moved Mendelssohn to number three on Steve Haskin's "Derby Dozen" for April 3.

He dropped back to ninth, where he experienced heavy kickback from the horses in front splashing over the muddy track surface.

[19][20] Despite the loss, O'Brien remained positive about the colt's competitiveness on dirt, with a goal of winning the Breeders' Cup Classic in November.

Although the "Midsummer Derby" was missing Justify, who had been retired due to injury, the field was considered highly competitive, led by Good Magic (Haskell Invitational), Canadian filly Wonder Gadot (Queen's Plate), Gronkowski (second in the Belmont Stakes), Bravazo (second in the Preakness) and Catholic Boy (Belmont Derby Invitational).

[2] In the Jockey Club Gold Cup at Belmont Park on 29 September Mendelssohn was matched against older horses and started the 4.3/1 second favourite.

After setting the pace he led the field into the straight but was overtaken approaching the final furlong and came home fifth behind Accelerate, Gunnevera, Thunder Snow and Yoshida, beaten two and a quarter lengths behind the winner.

He was the first three-year-old to finish and the horses coming home behind included West Coast, Discreet Lover, Catholic Boy, Mind Your Biscuits, McKinzie (Pennsylvania Derby) and Roaring Lion.

Mendelssohn made his final start of the year in the Cigar Mile on 1 December, finishing fourth after tracking a fast early pace set by Patternrecognition.