C61

C61 may refer to:
 * ARM Cadete Vicente Suarez, an Admirable-class minesweeper of the Mexican Navy
 * Bill C-61 (39th Canadian Parliament, 2nd Session), an act to amend the Copyright Act
 * Caldwell 61, a galaxy
 * Caudron C.61, a French civil transport biplane
 * Fairchild C-61 Forwarder, an American military aircraft
 * JNR Class C61, a class of Japanese steam locomotive
 * Prostate cancer
 * Reduction of Hours of Work (Textiles) Convention, 1937 of the International Labour Organization
 * Ruy Lopez, a chess opening