Sir Nicholas Throckmorton (or Throgmorton) (c. 1515/1516 – 12 February 1571) was an English diplomat and politician, who was an ambassador to France and played a key role in the relationship between Elizabeth I and Mary Queen of Scots.

Early years
After the death of Edward VI in 1553, during the short-lived attempt to place Lady Jane Grey on the throne, Throckmorton tried to keep contact with both supporters of both her and Queen Mary Tudor. Eventually he began to support the latter.
However, in January 1554 he was suspected of complicity in Wyatt's Rebellion and arrested. Later historians have suspected he was at least involved either because of his Protestantism or due to his dismay on the growing Spanish influence in the court.
Throckmorton was brought to trial at the Guildhall on 17 April of that year. He managed to convince the jury of his innocence even if the court was openly hostile to him. As a result, the court fined and imprisoned the jury and sent Throckmorton to the Tower. When he was released the next year, he fled to France in exile. Though there were people who wanted to put him to trial again, he was pardoned in 1557, and was employed by Queen Mary.

Elizabeth's court
After Elizabeth's accession Throckmorton rose rapidly into favour due to his personal acquaintance to her, sending her advice in the formation of her government. She followed some of that advice. He became Chief Butler and chamberlain of the exchequer, and from May 1559 to April 1564 he was ambassador to France. Throckmorton continued to sent letters and messengers with advice to the Queen and she often followed them.
In these years Throckmorton also became acquainted with Mary Queen of Scots. He conducted the negotiations after her return to Scotland, and though he supported Reformation, he became her close friend, willing to do her favors.
As an ambassador Throckmorton encouraged Elizabeth to aid the Huguenots, and surreptitiously took a part in the war of religion. When Throckmorton returned to France from a brief trip to England in 1560, Roman Catholic leader, the Duke of Guise imprisoned him as a persona non grata. Guise was convinced that Throckmorton had been involved with the Tumult of Aboise, a Huguenot plot. Throckmorton later remarked that he was afraid he would be killed but was later released and retained his post as an ambassador.
In 1562, when religious violence began to intensify in France, Throckmorton wanted to support mediation efforts of Catherine de Medici. Later in 1562, when the Huguenot Prince of Condé had taken over Newhaven (modern-day Le Havre) in April, Throckmorton convinced the Queen to send military aid to Huguenots in what was later called the Newhaven expedition. English troops garrisoned Le Havre in October 1562 but soon fell afoul with Huguenots. After the negotiations, the Huguenots turned against the English. After outbreak of plague, they had to surrender the next year. Catherine de Medici was suspicious of Throckmorton's schemes, however, and when Elizabeth sent him to negotiate with her in 1563, she placed him under house arrest.
Elizabeth sent Sir Thomas Smith to negotiate his release. The two men soon begun to dislike each other and in one stage almost came to blows but Throckmorton was eventually released in 1564.

Envoy to Mary Queen of Scots
Throckmorton married Anne Carew, daughter of Sir Nicholas Carew, a Knight of the Garter, and they had ten sons and three daughters. Their daughter Elizabeth became the wife of Sir Walter Raleigh.
Contemporary political figures regarded Throckmorton with respect. One of these was Sir Francis Walsingham who had worked with Throckmorton in France. In 1560 William Cecil said he would be prepared to resign if Throckmorton would take his place and spoke well of him after his death, in spite of their constant disagreements. Some contemporaries also suspected that he was a gray eminence behind Robert Dudley.
At the time of his death he held the posts of the keeper of Brigstock Park, Northamptonshire; Justice of the Peace in Northamptonshire; and Chief Butler of England and Wales. London's Throgmorton Street is named after him.