| Yochlol | 10 | Fiend (demon, shapechanger) | Medium | 15 | 136 | | chaotic evil | | Monster Manual | | | | | | |
| Yeti | 3 | Monstrosity | Large | 12 | 51 | | chaotic evil | | Monster Manual (SRD) | 18 | 13 | 16 | 8 | 12 | 7 |
| Yeth hound | 4 | Fey | Large | 14 | 51 | fly | neutral evil | | Volo's Guide to Monsters | | | | | | |
| Yellow musk zombie | 0.25 | Undead | Medium | 9 | 33 | | unaligned | | Adventures (Tomb of Annihilation) | | | | | | |
| Yellow musk creeper | 2 | Plant | Medium | 6 | 60 | | unaligned | | Adventures (Tomb of Annihilation) | | | | | | |
| Yeenoghu | 24 | Fiend (demon) | Huge | 20 | 333 | | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Yan c bin | 18 | Elemental | Huge | 22 | 283 | fly | neutral evil | | Adventures (Princes of the Apocalypse) | | | | | | |
| Yagnoloth | 11 | Fiend (yugoloth) | Large | 17 | 147 | | neutral evil | | Mordenkainen's Tome of Foes | | | | | | |
| Xvart warlock of raxivort | 1 | Humanoid (xvart) | Small | 12 | 22 | | chaotic evil | | Volo's Guide to Monsters | | | | | | |
| Xvart | 0.12 | Humanoid (xvart) | Small | 13 | 7 | | chaotic evil | | Volo's Guide to Monsters | | | | | | |
| Xorn | 5 | Elemental | Medium | 19 | 73 | | neutral | | Monster Manual (SRD) | 17 | 10 | 22 | 11 | 10 | 11 |
| Wyvern | 6 | Dragon | Large | 13 | 110 | fly | unaligned | | Monster Manual (SRD) | 19 | 10 | 16 | 5 | 12 | 6 |
| Wraith | 5 | Undead | Medium | 13 | 67 | fly | neutral evil | | Monster Manual (SRD) | 6 | 16 | 16 | 12 | 14 | 15 |
| Worg | 0.5 | Monstrosity | Large | 13 | 26 | | neutral evil | | Monster Manual (SRD) | 16 | 13 | 13 | 7 | 11 | 8 |
| Wood woad | 5 | Plant | Medium | 18 | 75 | | lawful neutral | | Volo's Guide to Monsters | | | | | | |
| Wolf | 0.25 | Beast | Medium | 13 | 11 | | unaligned | | Monster Manual (SRD) | 12 | 15 | 12 | 3 | 12 | 6 |
| Winter wolf | 3 | Monstrosity | Large | 13 | 75 | | neutral evil | | Monster Manual (SRD) | 18 | 13 | 14 | 7 | 12 | 8 |
| Winter eladrin | 10 | Fey (elf) | Medium | 19 | 127 | | chaotic neutral | | Mordenkainen's Tome of Foes | | | | | | |
| Winged kobold | 0.25 | Humanoid (kobold) | Small | 13 | 7 | fly | lawful evil | | Monster Manual (BR) | 7 | 16 | 9 | 8 | 7 | 8 |
| Will o wisp | 2 | Undead | Tiny | 19 | 22 | fly | chaotic evil | | Monster Manual (SRD) | 1 | 28 | 10 | 13 | 14 | 11 |
| Wild dog alpha | 1 | Beast | Large | 12 | 26 | | unaligned | | Extra (Adventurers League) | 17 | 15 | 13 | 3 | 12 | 8 |
| Wild dog | 0.12 | Beast | Medium | 12 | 5 | | unaligned | | Extra (Adventurers League) | 13 | 14 | 12 | 3 | 12 | 7 |
| Wight | 3 | Undead | Medium | 14 | 45 | | neutral evil | | Monster Manual (SRD) | 15 | 14 | 16 | 10 | 13 | 15 |
| White dragon wyrmling | 2 | Dragon | Medium | 16 | 32 | fly, swim | chaotic evil | | Monster Manual (SRD) | 14 | 10 | 14 | 5 | 10 | 11 |
| White abishai | 6 | Fiend (devil) | Medium | 15 | 68 | fly | lawful evil | | Mordenkainen's Tome of Foes | | | | | | |