Thomas Baty (8 February 1869 – 9 February 1954), also known as Irene Clyde, was an English international lawyer, writer, and activist. Baty was a legal adviser to the Japanese Foreign Office from 1916 to 1952 and wrote on international law. Under the name Irene Clyde, Baty co-founded and edited the journal Urania (1916–1940), which opposed binary classifications of gender. Modern scholars have described Baty in differing terms, including non-binary, genderfluid, transgender, and trans woman.

Baty studied at The Queen's College, Oxford and Trinity College, Cambridge, and later held academic and legal appointments. Under the name Irene Clyde, Baty published the novel Beatrice the Sixteenth (1909), which depicts a feminist utopian society without sex distinction, and founded the short-lived Aëthnic Union. Baty began advising the Japanese government in 1916 and was awarded the Order of the Sacred Treasure, third class in 1920 and second class in 1936.

In Japan, Baty developed a legal philosophy based on effective territorial control as the basis for recognition of states. Baty used this argument to support Japanese policy in Manchuria and China, represented Japan in international contexts including the League of Nations, and continued working in Japan during World War II. After the war, the British government considered prosecution for treason but instead revoked Baty's British citizenship. Baty remained in Japan and advised the government until 1952.

Thomas Baty was born on 8 February 1869 in Stanwix, Cumberland, the eldest child of Mary (née Matthews) and the cabinet maker William Thomas Baty. Baty had a sister named Anne. William died when Baty was seven. T. Maait Pepperell writes that Baty then formed a close relationship with Mary and Anne.

Peter Oblas writes that Baty's uncles financially supported the family, enabling a middle-class home shaped by the Victorian ideal of the "feminine home". Baty attended Carlisle Grammar School and won a scholarship to The Queen's College, Oxford in 1888.

Baty completed a B.A. in jurisprudence in 1892. Baty was called to the bar in 1898, and later earned an LL.M. from Trinity College, Cambridge in June 1901, a D.C.L. from Oxford the same year, and an LL.D. from Cambridge in 1903. Baty was a Civil Law Fellow at Oxford and a Whewell Scholar at Cambridge.

Baty also wrote under the name Irene Clyde. Jana Funke writes that Clyde advocated the abolition of male dominance, challenged gender binaries, examined the fluidity of biological sex, criticised heterosexual marriage and biological reproduction, and celebrated female-female relationships.

In 1909, Clyde published the feminist utopian novel Beatrice the Sixteenth. Set in Armeria, it describes a genderless society whose members have feminine characteristics and form life partnerships. The novel examines same-sex love and the gender binary. Maria Aline Seabra Ferreira describes it as a precursor to later feminist utopias and radical feminist theories of gender and sexuality.