Trial races for the Epsom Oaks are horse races during April and May which are contested by three-year-old fillies likely to run in The Oaks in early June.
The leading trial of recent years has been the 1,000 Guineas Stakes, which has been contested by eight subsequent winners of the Oaks in the last twenty-five years. The following table shows races classed at Listed level or above which served as a trial for an Oaks winner during the period 1992 to 2023.
| Race | Oaks winners from race 1992–2018 (won unless stated) | |
| Imagine (2nd) | ||
| Prix Finlande | Intrepidity | |
| Sariska (4th) | ||
| Balanchine (2nd), Moonshell (3rd), Reams of Verse (6th), Shahtoush (2nd) Kazzia, Casual Look (6th), Qualify (last), Minding, Love | ||
| Ouija Board, Talent, Taghrooda | ||
| Imagine (3rd) | ||
| Light Shift, Enable, Forever Together (2nd) | ||
| User Friendly, Lady Carla, Ramruma, Look Here (2nd). Anapurna | ||
| Reams of Verse, Alexandrova (2nd), Sariska, Snowfall, Soul Sister | ||
| Eswarah, Dancing Rain (2nd) | ||
| Love Divine, Snow Fairy | ||
| Intrepidity | ||
| Shahtoush (10th), Imagine, Qualify (10th), Minding (2nd), Tuesday (2nd) |
Notable early-season appearances by horses which ran in the 2012 Oaks.