Twentieth Army or 20th Army may refer to:

• Twentieth Army (Japan), a unit of the Imperial Japanese Army
• 20th Army (Soviet Union)
• 20th Group Army, People's Liberation Army
• 20th Guards Army, Soviet Union and Russia
• 20th Mountain Army (Wehrmacht), a German unit in WWII

• Synorbitalia
• S/Y Norda
• Synorthocladius
• Synorthodes
• Synosteosis
• Synostocephalus
• Synostoses
• Synot
• Syn otechestva
• Syn otechestva (journal)
• Syn otechestva (magazine)
• Synothele
• Synotis
• Synot Stare Mesto
• Synova Capital
• Synovate
• Synovel Collabsuite
• Synovial capsule
• Synovial chondrometaplasia
• Synovial cyst
• Synovial (disambiguation)
• Synovial Fluid
• Synovialosarcoma
• Synovial sarcoma, X breakpoint
• Synovial sheath