Ku. Alagirisami (Tamil: கு. அழகிரிசாமி, 23 September 1923 – 5 July 1970) was a Tamil writer from Tamil Nadu, India.
He was born in Idaicheval Chathirapatti village near Kovilpatti. He was a childhood friend of Ki. Rajanarayanan. He completed his SSLC and worked as a teacher and then as a clerk in the registrar office. He later became a journalist and wrote for Tamil publications like Tamil Mani, Sakthi and Prasanda Vikatan. His first short story Urakkam Kolluma was published in Ananda Bodhini in 1943. He became a sub-editor at Sakthi in 1947. He was a friend and contemporary of Vallikannan, Pudumaipithan and T. M. Chidambara Ragunathan.
His first short story collection – Ku. Alagirisamy kathaigal was published in 1952 with a foreword from Kalki Krishnamurthy. In 1953, he went to Malaysia to work in Tamil Nesan. He married Seethalakshmi in 1955. During 1960-65 he worked as a sub-editor in Navasakthi. He freelanced during 1965-70. He worked at Soviet Nadu for a few months until his death. In 1967, the Government of Tamil Nadu’s Tamil development department awarded a prize for his play Kavichakravarthi (lit. Emperor among poets). He was noted for his short stories. In 1970, he was awarded the Sahitya Akademi Award for Tamil posthumously for his short story collection Anbalippu.