Ah, the age-old question. How many countries are there on Earth? The answer, of course, depends on who you ask. For the purposes of this discussion, we'll go with the definition of "country" used by the United Nations.
According to the UN, there are 193 member states, plus two observer states (the Holy See and Palestine). However, this number is somewhat misleading, as a number of these countries are not universally recognized. For example, Taiwan is not recognized by the UN, but it is recognized by most other countries. Similarly, Kosovo is recognized as an independent country by over 100 nations, but it is not a member of the UN.
So, if we're going strictly by the UN's definition, there are 195 countries in the world. But in reality, the number is probably closer to 200.