The Lady Megan Arvon Lloyd George (22 April 1902 to 14 May 1966) was a British politician, the first female Member of Parliament for a Welsh constituency, and Deputy Leader of the Liberal Party. She later became a Labour MP.

The youngest child of David Lloyd George, she was born in Wales, at Criccieth in Caernarfonshire, in what is now Gwynedd. Like her brother Gwilym (later created Viscount Tenby), she followed her father into politics. After her father was raised to the Peerage as Earl Lloyd George of Dwyfor, she was known as the Lady Megan Lloyd George.

She became the first female MP in Wales when she won Anglesey for the Liberals in 1929. She refused to support Ramsay MacDonald's National Government in 1931 and successfully held Anglesey as an Independent Liberal until 1943. She held the seat again as a Liberal from 1945 to 1951.

Prominent among the radicals in the Liberal Party, she opposed what she saw as the party's drift away from her father's brand of liberalism. In 1949 she was named Deputy Leader of the party in a bid to create unity, but after losing her seat she stood down in 1952 and in 1955 defected to Labour. In 1957 she stood against the Liberals as the Labour Party candidate in a by-election in Carmarthen and won the seat from them, which she held until her death in 1966.

Throughout the 1940s and 50s Lloyd George campaigned for a Welsh assembly and the creation of a Secretary of State for Wales.