Memoir (1887 – 1908) was a dual classic-winning British Thoroughbred racehorse and broodmare. As a two-year-old in 1889 she showed considerable promise as she won the last three of her six races. In the following spring she appeared an unfortunate loser when stable arrangements prevented her from beating Semolina in the 1000 Guineas but she went on to win the Newmarket Stakes, Oaks Stakes, Nassau Stakes, St Leger and Newmarket Oaks. She added a win in the July Cup before being retired at the end of 1891. Although she produced no major winners, she had an enduring influence through her daughter, Miss Gunning.

Memoir was a brown mare bred in England by the National Stud. As a yearling she was put up for auction and bought for 1,500 guineas by William Cavendish-Bentinck, 6th Duke of Portland. She was sent into training with the Duke's private trainer George Dawson at the Heath House stable in Newmarket, Suffolk.

She was from the first crop of foals sired by the undefeated racehorse St Simon who went on to win nine sires’ championships. Her dam, Quiver produced Memoir full-sister La Fleche, as well as the influential broodmares Maid Marian and Satchel.

Memoir ran six times as a juvenile in 1889 and was beaten on her first three starts before recording her first success when she won the Bradford Plate, worth £436 at Leicester Racecourse in September. At Newmarket Racecourse in October she added victories in the Zetland Stakes (not the current race of the same name) and the Prendergast Stakes. She ended the season with earnings of £1,308.

In the 1000 Guineas over the Rowley Mile at Newmarket on 2 May Memoir started the 10/1 second choice in the betting behind Semolina, the 1/2 favourite, who was also owned by the Duke of Portland and trained by Dawson. Ridden by George Barrett Memoir finished second of the ten runners, beaten three quarters of a length by her more fancied stablemate. In accordance with the rules at the time, the Duke had "declared to win" with Semolina, and Memoir, who appeared to be capable of winning the race, was eased down in the closing stages, thus forfeiting her chance of victory. According to some reports Memoir was "fighting for her head" throughout the race and Barrett had to pull hard on the bridle to prevent her from winning.

At the next Newmarket meeting on 21 May, Memoir was moved up in distance and matched against male opposition in the Newmarket Stakes over ten furlongs for which he started the 6/1 second favourite behind Leopold de Rothschild's colt Le Nord. She was equipped with blinkers for the first time and after disputing the lead from the start she stayed on strongly to win by a short head from Blue Green with Le Nord in third.

On 6 June Memoir, with John Watts in the saddle, was one of seven fillies to contest the 112th running of the Oaks Stakes over one and a half miles at Epsom Racecourse. The Middle Park Plate winner Signorina started even money favourite ahead of Memoir (100/30) and Semolina, while the only one of the other four to be given any chance was Ponza (100/8). Memoir was restrained towards the rear as Semolina set the early pace, but made steady progress from half way and moved into contention in the straight. She took the lead entering the final furlong and defeated Signorina to win by three quarters of a length with Ponza taking third place ahead of Semolina. Her winning time of 2:40.8 was a new record for the race.

At Leicester on 9 July Memoir contested the £8,500 Prince of Wales Stakes over one mile and finished second behind the 2000 Guineas winner Surefoot. On 1 August she turned to all female competition in the Nassau Stakes over one mile at Goodwood Racecourse and won from Star and Dearest in a time of 1:49.6.