What were the results of the Thirty Years' War?

As a result of the Thirty Years' War (1618-1648), Switzerland and the Netherlands became independent; Germany became fragmented and its population was greatly reduced; and France soon became a dominant power in western continental Europe. The war also saw Spain begin to decline as a colonial power.

The Thirty Years' War was the last major religious war in mainland Europe, and the destruction wrought by mercenary soldiers led many nations to begin developing standing national armies instead.

The Peace of Augsburg agreements (1555) were endorsed. The recognition of the rights of Protestants greatly displeased Rome, where the Westphalian treaties were denounced by Pope Innocent X.

(for more on the political consequences, see the related link)
Another answer:
The Thirty Years' War devastated entire regions, with famine and disease. The war killed soldiers and civilians directly, caused famines, destroyed people's livelihoods, disrupted trade between countries, postponed marriages and childbirth, and forced large numbers of people to relocate.
The war also bankrupted most of the powers involved , except the Dutch Republic. The war altered the structure of political power in Europe.