What is the 50th largest country in the world?

Yemen.

In terms of countries' area, the Republic of Yemen is the 50th largest. Its area is approximately 528,000 km2, or 204,000 square miles. It is smaller than Kenya (ranked 49th, with an area of 580,000 km2), but is also larger than Thailand (ranked 51st, with an area of 513,000 km2). Therefore, Yemen is the 50th largest country in the world.