Channel 21, or TV 21 or TV21 may refer to:

• Channel 21 (Germany), a television channel in Germany; formerly known as "RTL Shop"
• TV 21 (North Macedonia), a television channel in North Macedonia
• El Watania 2, a television channel in Tunisia; formerly known as "Canal 21"
• L'Équipe 21, a television channel in France
• ETC-21, a television station in Quezon City, Philippines
• Canal Orbe 21, a television station in Buenos Aires, Argentina; formerly known as "Canal 21"
• Citytv Bogota, a television station in Bogota, Colombia
• Enlace Nicaragua, a Christian television station in Nicaragua
• Rede 21, a defunct Brazilian television network
• RTL9, a Luxembourgish French-language channel, formerly known as "Canal 21" in France
• Télé 21, the former name of Belgian-French television channel Tipik (TV channel)

• CHNU-DT-1, virtual channel 21 in Victoria, British Columbia
• CJON-DT, virtual channel 21 in St. John's, Newfoundland and Labrador

• XHTIT-TDT, virtual channel 21, carries Azteca 7 in Tijuana, Baja California
• XHCDM-TDT, virtual channel 21 in Mexico City

• Channel 21 TV stations in Canada
• Channel 21 TV stations in Mexico
• Channel 21 digital TV stations in the United States
• Channel 21 low-power TV stations in the United States

• TV21, an early 1980s British new wave band
• TV Century 21, a weekly British children's comic published during the 1960s

• 21 (disambiguation)
• Channel 21 branded TV stations in the United States
• Channel 21 virtual TV stations in the United States