Arthur Bell Nicholls (6 January 1819 – 3 December 1906) was the husband of the English novelist Charlotte Brontë.
Between 1845 and 1861 Nicholls was one of Patrick Brontë's curates and was married to his eldest surviving child, Charlotte, for the last nine months of her life. He cared for Patrick Brontë after Charlotte Brontë's death and spent the rest of his life in the shadow of her reputation. He returned to his native Ireland, remarried and left the church.
Nicholls was one of ten children born to William Nicholls, a Presbyterian farmer and Margaret Bell Nicholls, a member of the Anglican Church of Ireland in Killead, County Antrim, in Ireland. He was educated at the Royal Free School in Banagher, County Offaly, whose headmaster was his uncle, Alan Bell. In 1836 Nicholls entered Trinity College, Dublin, from where he graduated in 1844.
Nicholls was ordained as a deacon in 1845 in Lichfield and became Patrick Brontë's curate in June that year. Charlotte Brontë said of him that he appeared to be a respectable young man who read well, and she hoped that he would give satisfaction. Although he visited the poor of the parish practically every afternoon, he was considered to be strict and conventional, and in 1847 he carried out a campaign to prevent women from hanging their washing out to dry in the cemetery. Charlotte noted sadly that while he was away on holiday in Ireland many parishioners said that they hoped he would not return. He began to develop closer relations with Charlotte, who by that time had written Jane Eyre, and they conducted a friendly exchange of letters. In December 1848, he conducted the funeral service of Emily Brontë.
On 13 December 1852 Nicholls asked Charlotte for her hand in marriage. Charlotte's father vehemently refused to approve the union on the grounds that a poor Irish pastor should never be bold enough to suggest marrying his famous daughter. In 1853 Nicholls announced his intention to leave for Australia as a missionary, but he later changed his mind despite collecting references (including one from Patrick Brontë) and a farewell gift from the parishoners. He was re-deployed for several months to another parish, but he had several secret meetings with Charlotte in Haworth. Little by little Charlotte became persuaded by Nicholls, and in February 1854 her father finally gave his permission for the visits. Arthur Nicholls and Charlotte Brontë were married on 29 June 1854 in her father's church at Haworth. Patrick Brontë decided on the day of the ceremony not to attend, so Charlotte was led to the altar by Margaret Wooler, her former schoolmistress at Roe Head School. They honeymooned in Wales and Ireland before returning to live with Charlotte's father at Haworth Parsonage.