Animal Fighting Spectator Prohibition Act of 2013 - Amends the Animal Welfare Act to prohibit any person from knowingly attending an animal fighting venture or causing a minor (a person under the age of 18) to attend such a venture.

Subjects any person who: (1) knowingly attends such venture to a fine and/or imprisonment for up to a year for each violation, and (2) knowingly causes a minor to attend such venture to a fine and/or imprisonment for up to three years for each violation.