Yes, the Gatwick Express; it leaves every 15min, and will get you to Victoria Station (with no stops) in 30min. A one-way ticket will cost around £20 (approx. €23-24). You could also buy an Oyster card (a prepaid London travel card) from Gatwick Station for more discounts on this route and other routes around London. There are several other train routes into London, but this is the fastest and most direct.