Ralph W. Munn (September 19, 1894 – January 2, 1975) was an eminent figure in the field of American and international library and information science. Recognized by the journal American Libraries as one of "100 of the most important leaders we had in the 20th century", and described as an "administrator, educator, and author ... known for his fairness, clarity, and grace", he was also widely known within the profession as "the father of the modern library movement in Australia and New Zealand".