The 2015 FIVB Volleyball Men's U21 World Championship was the eighteenth edition of the FIVB Volleyball Men's U21 World Championship, which was hosted by Mexico from 11 to 20 September 2015 in the cities of Mexicali and Tijuana.

Russia, won the tournament after defeating Argentina 3-2 in the final match, thus securing the country's tenth title and the third in a row, after winning the editions of 2011 in Brazil and 2013 in Turkey.

[2] The FIVB Sports Events Council confirmed a proposal to streamline the number of teams participating in the Age Group World Championships on 14 December 2013.

[3] Teams were seeded in the first two positions of each pool following the Serpentine system according to their FIVB U21 World Ranking as of December 2014.

[4] FIVB reserved the right to seed the hosts as head of Pool A regardless of the U21 World Ranking.