J1

J1, J01, J.I, J-I or J-1 may refer to:

• J-I rocket, a Japanese solid rocket expendable launch vehicle
• J1 type submarine, a WWII Imperial Japanese Navy cruiser submarines class
• HMS J1, a WWI British submarine
• J-1 visa, a type of U.S. visa for exchange visitors (e.g. students coming to the USA for an internship)
• J-1 World Heavyweight Championship, a wrestling competition
• AEG J.I, a World War I German ground attack aircraft
• Albatros J.I, a 1917 German ground-attack single-engine biplane aircraft
• ATC code J01 Antibacterials for systemic use, a subgroup of the Anatomical Therapeutic Chemical Classification System
• DSER Class J1, a Dublin and South Eastern Railway Irish steam locomotive
• Haplogroup J1 (Y-DNA), a Y-DNA haplogroup
• Janko group J1 in mathematics
• Junkers J 1, a 1916 German aircraft
• Junkers J.I, a 1917 German aircraft
• Lawrance J-1, an early 1920s engine used in American aircraft
• LB&SCR J1 class, a British LB&SCR locomotive
• PRR J1, an American PRR steam locomotive
• S/2003 J 1, a former name for Eukelade, a retrograde irregular satellite of Jupiter
• J1 World Tour, a concert tour by Taiwanese singer Jolin Tsai
• J1 Live Concert, a live album by Taiwanese singer Jolin Tsai
• J1 denotes the Personnel, or Human Resources function of a U.S. Joint Command (for example: the J-1 Directorate in Special Operations Command Europe refers to the Human Resources Directorate)
• First-order Bessel function of the first kind, $j_1$
• The J1 League, the top division of Japanese association football
• J01 : acute sinusitis ICD-10 code
• J1 (glider) refers to a Yugoslavian glider