13th man or thirteenth man may refer to:

• 13th man, a reference to the fans of a team playing Canadian football, where 12 players are usually on the field
• The 13th Man, a 1937 American mystery film
• The Thirteenth Man, a 1917 Italian drama silent film

• Church of St. Mark, Natland
• Church of St Mark, Natland
• Church of St Mark, Preston
• Church of St. Mark, Preston
• Church of St Mark, Reading
• Church of St. Mark, Saltney
• Church of St Mark, Saltney
• Church of St Mark, Sheffield
• Church of St Mark, Swindon
• Church of St. Mark, Swindon
• Church of St. Mark, Zagreb
• Church of St. Martin, Bowness
• Church of St Martin, Bowness
• Church of St. Martin, Bowness-on-Windermere
• Church of St Martin, Bowness-on-Windermere
• Church of St. Martin de Porres
• Church of st Martin in Bled (Slovenia)
• Church of St. Martin in Kaczanowo
• Church of St. Martin in the Wall
• Church of St. Martin in Valaurie
• Church of St. Martin, Kaczanowo
• Church of St Martin (Slovenia)
• Church of St. Martin, Windermere
• Church of St Martin, Windermere
• Church of St. Mary