 Boris KarloffThe Monster | The Monster |
 Colin CliveHenry Frankenstein | Henry Frankenstein |
 Valerie HobsonElizabeth | Elizabeth |
 Ernest ThesigerDoctor Pretorius | Doctor Pretorius |
 Elsa LanchesterMary Wollstonecraft Shelley / The Monster's Mate | Mary Wollstonecraft Shelley / The Monster's Mate |
 Gavin GordonLord Byron | Lord Byron |
 Douglas WaltonPercy Bysshe Shelley | Percy Bysshe Shelley |
 Una O'ConnorMinnie | Minnie |
 E. E. CliveBurgomaster | Burgomaster |
 Lucien PrivalButler | Butler |
 O. P. HeggieHermit | Hermit |
 Dwight FryeKarl | Karl |
 Reginald BarlowHans | Hans |
 Mary GordonHans' Wife | Hans' Wife |
 Anne DarlingShepherdess | Shepherdess |
 Ted BillingsLudwig | Ludwig |
 Billy BartyBaby (uncredited) | Baby (uncredited) |
 Robert AdairHunter in Woods (uncredited) | Hunter in Woods (uncredited) |
| NNorman AinsleyArchbishop (uncredited) | Archbishop (uncredited) |
| FFrank BensonVillager (uncredited) | Villager (uncredited) |
 Maurice BlackGypsy (uncredited) | Gypsy (uncredited) |
 Walter BrennanPeasant (uncredited) | Peasant (uncredited) |
| MMae BruceVillager (uncredited) | Villager (uncredited) |
| AA.S. ByronKing Homunculus (uncredited) | King Homunculus (uncredited) |
 John CarradineLost Hunter at Hermit's Cottage (uncredited) | Lost Hunter at Hermit's Cottage (uncredited) |
 D'Arcy CorriganProcession Leader (uncredited) | Procession Leader (uncredited) |
 Grace CunardVillager (uncredited) | Villager (uncredited) |
| JJ. Gunnis DavisUncle Glutz (uncredited) | Uncle Glutz (uncredited) |
| MMarie DeForrestBallerina (uncredited) | Ballerina (uncredited) |
 Elspeth DudgeonGypsy's Mother (uncredited) | Gypsy's Mother (uncredited) |
