Arthur Nicholas Whistler Colahan (12 August 1884 – 15 September 1952) was an Irish medical doctor, British Army officer and songwriter.
He began his medical career in the County Infirmary in Galway, and then moved to Holles Street maternity hospital.
He joined the Royal Army Medical Corps, and was badly affected by mustard gas in India.
His most famous work is Galway Bay, which was popularised by Bing Crosby, and was the biggest selling record of all time at one stage.
Other songs written by Colahan included Maccushla Mine, Asthoreen Bawn, Until God's Day, The Kylemore Pass and The Claddagh Ring.