Twenty20 International Cricket, also called T20I, is the format of cricket that revolutionized the game when it began in 2003, accumulating a new audience for cricket.  The fundamental rules of the T20I are the same as for the other form, but innings are restricted to 20 overs. Within a short span, T20I evolved into the most widespread and lucrative form of cricket. England and Wales Cricket Board founded the official rules for T20I. The T20I tournament was played for the first time in 2003 between England and Australia.

1. Bangladesh 

Bangladesh is the most unsuccessful team in T20I history. The squad started playing T20I in 2006. They have played 123 games and lost 78 of them with a win percentage of 35.53. The team took part in seven T20I world cups but didn't have any memorable performances.

2. Sri Lanka

The second country on the list of the unsuccessful teams ofT20I is Sri Lanka. They started playing T20I games in 2006 and played 148 games and lost 77 with a win percentage of 46.57. They took part in seven T20I world cups and have won the trophy once in 2014.

3. West Indies

The T20I champions and the most successful team in T20I world cups yet have lost many matches and are at 3rd position in the list. They started playing T20I games in 2006 and have played 152 games and lost 77 of them with a win percentage of 45.1. They have appeared six times in the T20I world cups and have won two the 2012 and 2016 cups.

4. New Zealand

New Zealand is one of the successful teams in cricket but not that successful in T20I. They started playing the game in 2005 and have played 160 games and lost 70 with a win percentage of 52.56. They took part in seven T20I world cups, and their best performance was in 2021 where they were the runner-ups.

5. Zimbabwe

Zimbabwe started playing the game in 2006 and have played 96 games and lost 70 of them with the worst win percentage of 26.04. They played five T20I world cups and have reached the group stage in all.

6. Australia

The current T20I champions started playing T20I in 2005 and have played 153 games and lost 69 of them with a win percentage of 53.33. They played seven T20I world cups and have won the 2021 edition by dominating throughout the tournament

7. Pakistan 

Pakistan is one of the best sides in T20I in the current time and started playing the game in 2006 and have played 189 games and lost 64 of them with a win percentage of 64.4. They took part in seven T20I world cups and have won once in 2009

8. England

The current no.1 T20I team in the world and one of the first countries to play T20I started playing the game in 2005 and have played 143 games and lost 61 of them with a win percentage of 55.07. They have played seven T20I world cups and have won once in 2010.

9. South Africa

One of the most dangerous sides of T20I cricket, the Proteas started playing T20I in 2005 and have played 147 games and lost 60 of them with a win percentage of 58.58. They took part in six T20I world cups and have reached the semi-final twice in 2009 and 2014.

10. Ireland