The English Gothic Novel: A Brief Overview
According to Oates (2003), The English Gothic novel began with Horace Walpole's The Castle of Otranto (1765), which was enormously popular and quickly imitated by other novelists and soon became a recognizable genre. To most modern readers, however, The Castle of Otranto  is dull reading; except for the villain Manfred, the characters are insipid and flat; the action moves at a fast clip with no emphasis or suspense, despite the supernatural manifestations and a young maiden's flight through dark vaults. But contemporary readers found the novel electrifyingly original and thrillingly suspenseful, with its remote setting, its use of the supernatural, and its medieval trappings, all of which have been so frequently imitated and so poorly imitated that they have become stereotypes. The genre takes its name from Otranto's  medieval–or Gothic–setting; early Gothic novelists tended to set their novels in remote times like the Middle Ages and in remote places like Italy (Matthew Lewis's The Monk, 1796) or the Middle East (William Beckford's Vathek, 1786).
What makes a work Gothic is a combination of at least some of these elements:

The Gothic creates feelings of gloom, mystery, and suspense and tends to the dramatic and the sensational, like incest, diabolism, necrophilia, and nameless terrors. It crosses boundaries, daylight and the dark, life and death, consciousness and unconsciousness (Henessy, 1978). Sometimes covertly, sometimes explicitly, it presents transgression, taboos, and fears–fears of violation, of imprisonment, of social chaos, and of emotional collapse. Most of us immediately recognize the Gothic (even if we don't know the name) when we encounter it in novels, poetry, plays, movies, and TV series. For some of us–and I include myself– safely experiencing dread or horror is thrilling and enjoyable.
Elements of the Gothic have made their way into mainstream writing. They are found in Sir Walter Scott's novels, Charlotte Brontë's Jane Eyre, and Emily Brontë's Wuthering Heights  and in Romantic poetry like Samuel Coleridge's "Christabel," Lord Byron's "The Giaour," and John Keats's "The Eve of St. Agnes." A tendency to the macabre and bizarre which appears in writers like William Faulkner, Truman Capote, and Flannery O'Connor has been called Southern Gothic (Henessy, 1978).

Wuthering Heights as a Victorian Novel
Wuthering Heights is in the same ethical and moral tradition as the other great Victorian novels. Its criticism of society is as fierce as Charlotte Bronte's or Dickens' [Much] of the same spirit interfuses the novels of Charlotte and Emily Bronte. For both writers, society and what passes for civilization are synonymous with selfishness. Both show family life as a sort of open warfare, a deadly struggle for money and power. Both see organized religion as ineffective or hypocritical or so cold and harsh as to be inhumane and deflected from true Christian ideals. The characters in Charlotte Bronte's first two novels have to face many of the same problems confronting the characters in Wuthering Heights, and they reach the same conclusions. Both William Crimsworth (in The Professor) and Jane Eyre reject the master-slave relationship as static and stultifying and come to the teacher-pupil relationship as the one that allows for growth and the fulfillment of human potential. Similarly, Catherine Linton and Hareton Earnshaw see the futility of Heathcliff's desire for revenge and domination (his seeing the world solely in terms of the master-slave relationship when love fails him) and affirm civilization and civilized values in terms of the teacher-pupil relationship.