Benjamin Boothby (5 February 1803 – 21 June 1868) was a judge in the colony of South Australia. He was removed from office for misbehaviour, one of four Australian supreme court judges removed in the 19th century. He was the father of electoral reformer William Boothby.

Benjamin Boothby was born in Doncaster, Yorkshire, England, on 5 February 1803.

Boothby assisted Sir Thomas Wilde in his electoral campaigns and read in his chambers. He was called to the Bar at Gray's Inn in 1825.

In 1853, Boothby was appointed a Judge of the Supreme Court of South Australia. This was the last appointment of a South Australian judge by the Colonial Office.

Boothby, in a series of judgments, adopted a pedantic approach to Imperial Law, holding a number of South Australian statutes invalid, including those which introduced the Torrens system of land registration in the colony.

Boothby also asserted that the Parliament of South Australia had not been validly constituted since the enactment of the Constitution Act 1855–56.

In 1865, partly in response to the approach taken by Boothby, the (British) Imperial Parliament passed the Colonial Laws Validity Act 1865, confirming the authority of the colonial parliament to pass legislation different from that passed by the Imperial Parliament. However, Boothby continued to create difficulties, refusing to acknowledge the authority of the Attorney-General and challenging the legality of the appointments of the other two judges of the Supreme Court on the supposed basis that only British-trained (in England, or Ireland; rather than in Australia) barristers could be appointed.

Proceedings were commenced to remove Boothby from office on the ground of misbehaviour. The charges were found proved and the judge was "amoved" on 29 July 1867. Boothby took formal steps to appeal this decision to the Privy Council, but died before the appeal was heard.