
Thirty-five countries from around the world participated in PIRLS 2001, and forty-one countries participated in PIRLS 2006. Forty-eight countries participated in PIRLS 2011.
| Countries | 2001 | 2006 | 2011 |
| Africa | |||
| Botswana | o | ||
| Morocco | o | o | o |
| South Africa | o | o | |
| Asia and Middle East | |||
| Azerbaijan | o | ||
| Chinese Taipei | o | o | |
| Hong Kong (SAR) | o | o | o |
| Indonesia | o | o | |
| Iran | o | o | o |
| Israel | o | o | o |
| Kuwait | o | o | o |
| Oman | o | ||
| Qatar | o | o | |
| Saudi Arabia | o | ||
| Singapore | o | o | o |
| Turkey | o | ||
| United Arab Emirates1 | o | ||
| Europe | |||
| Austria | o | o | |
| Belgium (Flemish) | o | ||
| Belgium (French) | o | o | |
| Bulgaria | o | o | o |
| Croatia | o | ||
| Cyprus | o | ||
| Czech Republic | o | o | |
| Denmark | o | o | |
| England | o | o | o |
| Finland | o | ||
| France | o | o | o |
| Georgia | o | o | |
| Germany | o | o | o |
| Greece | o | ||
| Hungary | o | o | o |
| Iceland | o | o | |
| Ireland | o | ||
| Italy | o | o | o |
| Latvia | o | o | |
| Lithuania | o | o | |
| Luxembourg | o | ||
| Macedonia, Republic of | o | o | |
| Malta | o | ||
| Moldova | o | o | |
| Netherlands | o | o | o |
| Norway | o | o | o |
| Poland | o | o | |
| Portugal | o | ||
| Romania | o | o | o |
| Russian Federation | o | o | o |
| Scotland | o | o | |
| Slovak Republic | o | o | o |
| Slovenia | o | o | o |
| Spain | o | o | |
| Sweden | o | o | o |
| North America | |||
| Canada2 | o | o | o |
| Trinidad and Tobago | o | o | |
| United States | o | o | o |
| Central America | |||
| Belize | o | ||
| Honduras | o | ||
| South America | |||
| Argentina | o | ||
| Colombia | o | o | |
| Oceania | |||
| Australia | o | ||
| New Zealand | o | o | o |
| Total | 35 | 41 | 48 |