The political terms "Left" and "Right" were first used during the French Revolution (1789–1799) and referred to seating arrangements in the French parliament. The anti-royalist revolutionaries seated themselves to the presiding officer’s left, while the more conservative, aristocratic supporters of the monarchy gathered to the right.

The distinctions later vanished for several years during the reign of Napoleon Bonaparte, but with the Bourbon Restoration and the beginning of a constitutional monarchy in 1814, liberal and conservative representatives once again took up their respective posts on the left and right of the legislative chamber. By the mid-19th century, “left” and “right” had entered the French vernacular as shorthand for opposing political ideologies. Political parties even began self-identifying as “center left,” “center right,” “extreme left” and “extreme right.”

The terms "left" and "right" were not used to refer to political ideology per se, but only to seating in the legislature. After 1848, the main opposing camps were the "democratic socialists" and the "reactionaries" who used red and white flags to identify their party affiliation. With the establishment of the Third Republic in 1871, the terms were adopted by political parties: the Republican Left, the Centre Right and the Centre Left (1871) and the Extreme Left (1876) and Radical Left (1881).

In British politics, the terms "right" and "left" came into common use for the first time in the late 1930s in debates over the Spanish Civil War.

Historically in America it seems the terms liberal and conservative have always been used more frequently. I cannot find a reference for the first usage of the words left and right as political terms in the United States. The best is a 2005 survey that showed American citizens were unfamiliar with the terms.