Professor Abraham Van Helsing (Dutch: [ˈaːbraːɦɑɱ vɑn ˈhɛlsɪŋ]) is a fictional character from the 1897 gothic horror novel Dracula written by Bram Stoker. Van Helsing is a Dutch polymath doctor with a wide range of interests and accomplishments, partly attested by the string of letters that follows his name: "MD, D.Ph., D.Litt., etc.", indicating a wealth of experience, education and expertise. He is a doctor, professor, lawyer, philosopher, scientist, and metaphysician. The character is best known through many adaptations of the story as a vampire slayer, monster hunter and the arch-nemesis of Count Dracula, and the prototypical and the archetypal parapsychologist in subsequent works of paranormal fiction. Some later works tell new stories about Van Helsing, while others, such as Dracula (2020) and I Woke Up a Vampire (2023) have characters that are his descendants.

In the novel, Professor Van Helsing is called in by his former student, John Seward, to assist with the mysterious illness of Lucy Westenra. Van Helsing's friendship with Seward is based in part upon an unknown prior event in which Van Helsing suffered a grievous wound, and Seward saved his life by sucking out the gangrene. It is Van Helsing who first realizes that Lucy is the victim of a vampire, and he guides Seward and his friends in their efforts to save Lucy.

Van Helsing had a son who died. He says that his son, had he lived, would have had a similar appearance to Lucy's suitor Arthur Holmwood ("My heart bleed for that poor boy, that dear boy, so of the age of mine own boy had I been so blessed that he live, and with his hair and eyes the same"). Consequently, Van Helsing developed a particular fondness for Holmwood. Van Helsing's wife went insane from grief after their son's death, but as a Catholic, he refuses to divorce her ("with my poor wife dead to me, but alive by Church's law, though no wits, all gone, even I, who am faithful husband to this now-no-wife").

Van Helsing is one of the few characters in the novel who is fully physically described in one place. In chapter 14, Mina Harker describes him as:

a man of medium height, strongly built, with his shoulders set back over a broad, deep chest and a neck well balanced on the trunk as the head is on the neck. The poise of the head strikes me at once as indicative of thought and power. The head is noble, well-sized, broad, and large behind the ears. The face, clean-shaven, shows a hard, square chin, a large resolute, mobile mouth, a good-sized nose, rather straight, but with quick, sensitive nostrils, that seem to broaden as the big bushy brows come down and the mouth tightens. The forehead is broad and fine, rising at first almost straight and then sloping back above two bumps or ridges wide apart, such a forehead that the reddish hair cannot possibly tumble over it, but falls naturally back and to the sides. Big, dark blue eyes are set widely apart and are quick and tender or stern with the man's moods.

— Mina Harker's Journal, chapter 14, Dracula

Van Helsing's personality is described by John Seward, his former student, thus:

He is a seemingly arbitrary man, this is because he knows what he is talking about better than anyone else. He is a philosopher and a metaphysician, and one of the most advanced scientists of his day, and he has, I believe, an absolutely open mind. This, with an iron nerve, a temper of the ice-brook, and indomitable resolution, self-command, and toleration exalted from virtues to blessings, and the kindliest and truest heart that beats, these form his equipment for the noble work that he is doing for mankind, work both in theory and practice, for his views are as wide as his all-embracing sympathy.