Sir Thomas George Knox KCMG (11 January 1824 – 29 July 1887) was an Ulster-Scots soldier and a diplomat, serving as consul-general in Siam from 1868 to 1879.

(1789–1862), rector of Maghera, County Londonderry, and his wife, Clara, daughter of the Right Hon.

[3] Siam was under Mongkut, who was opening the country to the West, and Knox functioned as a military adviser.

In the Front Palace crisis of 1874–5, Knox was absent at the outset in the United Kingdom, when supporters of Wichaichan challenged Chulalongkorn, and consular staff did what they could to calm matters.

A tense factional situation was precipitated into a power struggle when in March of that year Fanny Knox, his elder daughter, married a member of the royal family without the required permission.

Knox found his position undermined when the British government refused to back him with military force.