Fifa world ranking: 29
Ranking in Asia: 1
Previous Asian Cups: 13
Best performance: Champions (1968, 1972, 1976)
2015 Asian Cup: Quarter-finals
Nickname: Team Melli
Manager: Carlos Queiroz
Captain: Masoud Shojaei
Player to watch: Sardar Azmoun
Fixtures: January 7 v Yemen (Abu Dhabi); January 12 v Vietnam (Abu Dhabi); January 16 v Iraq (Dubai)
Turmoil and uncertainty have become the norm around Iran's national team, but Carlos Queiroz will look to push aside the distractions to end the country's 43-year Asian Cup title drought.
Iran last won Asian football's most coveted trophy in 1976, when they completed the third of three consecutive championship wins that mark the country out as one of continent's most successful ever.
But for all their achievements since that last triumph - a resume that includes five World Cup appearances and three gold medals at the Asian Games - the title the football-mad nation hankers after most has continued to prove elusive.
Fifa world ranking: 88
Ranking in Asia: 11
Previous Asian Cups: 8
Best performance: Champions (2007)
2015 Asian Cup: Fourth place
Nickname: Lions of Mesopotamia
Manager: Srecko Katanec
Captain: Mohammed Gassid
Player to watch: Bashar Resan
Fixtures: January 8 v Vietnam (Abu Dhabi); January 12 v Yemen (Sharjah); January 16 v Iran (Dubai)
Champions when they defied the odds in 2007, circumstances have scarcely improved for the Lions of Mesopotamia since, with security concerns back home having a major impact on preparations.
They reached the semi-finals in 2015, when they lost to South Korea, but many of the big name players that fired that campaign have since retired.
Slovenian coach Srecko Katanec took over in September but his side have struggled to find the net this year, which might complicate their passage from Group D into the knockout stages.
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Fifa world ranking: 100
Ranking in Asia: 17
Previous Asian Cups: 1
Best performance: Quarter-finals (2007)
2015 Asian Cup: Did not qualify
Nickname: Golden Dragons
Manager: Park Hang-seo
Captain: Que Ngoc Hai
Player to watch: Nguyen Quang Hai
Fixtures: January 8 v Iraq (Abu Dhabi); January 12 v Iran (Abu Dhabi); January 16 v Yemen (Al Ain)
South Korean Park Hang-seo has transformed expectations in Vietnam by taking the Under 23 side to the final of the Asian Cup in January and the semi-finals of the Asian Games tournament in August.
The senior team capped that, and triggered more wild celebrations around the country, when they beat Malaysia over two legs to win the Asean Football Federation (AFF) Championship in December.
Having been drawn in a tough group, they will do well to match their single appearance in the quarter-finals as co-hosts in 2007 but some in Vietnam are starting to believe Park and his players can do anything.
FIFA world ranking: 135
Ranking in Asia: 26
Previous Asian Cups: 0
Nickname: The Red Devils
Manager: Jan Kocian
Captain: Ala Al Sasi
Player to watch: Ala Al Sasi
Fixtures: January 7 v Iran (Abu Dhabi); January 12 v Iraq (Sharjah); January 16 v Vietnam (Al Ain)
Yemen make their debut appearance at the Asian Cup in the UAE after qualifying as runners-up from a group won by the Philippines and also featuring Tajikistan and Nepal. The civil war has had a major impact on the team's preparations, with the national side unable to play at home due to the security situation. They have also undergone a coaching change, with Slovakia's Jan Kocian replacing Abraham Mebratu in October.
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