Visa requirements vary depending from which country you come and your country's treaties and agreements it belongs too, what the purpose of your stay is, and how long you are planning to stay.

As a general rule, citizens of EU countries do not require a visa to enter Germany and a visa is not required for semi-annual visits of up to three months for nationals of those countries for which the European Community has abolished the visa requirement. A visa is always needed if you want to begin gainful employment in Germany.

For all the details about whether or not a visa is needed, how to obtain one, and how long it will take please check out the link at the bottom of the page.