Nope. The SPF of a sunscreen refers to the level of protection it provides against UVB rays only. In fact, many high SPF lotions do absolutely nothing against UVA rays, the rays which penetrate the skin more deeply and do more damage. Manufacturers in the United States, however, still make false claims that their lotions "block all harmful rays."
In Europe, such claims are illegal. In fact, the term "sunblock" has recently been banned.
So how does one sort through the hundreds of possibilities for suntan lotions? Thankfully the folks at the Environmental Working Group did the investigating for us. They compiled a list of the best lotions, as well as a list of the worst. (Remember, a low score mean the product is safer.)