One of the most famous Walther models was introduced in 1929. This was the Model PP. This pistol was to continue in production throughout the second world war and is, in fact, still in production. The Model PP is a straight blowback design containing a number of features developed from previous models, in particular the Model 8. The early production weapons were extremely well finished but later weapons produced during the latter part of the war had the signal pin indicator missing and a poor exterior finish.

The Model PP was often issued to German troops owing the shortage of standard caliber weapons. Although the original caliber was .32 ACP, it has also been produced in .22 Long Rifle and .380 ACP as well as a rare variation in .25 ACP. The designation "PP" is merely derived from the fact that the original use of the pistol was for the police; thus Polizei Pistole. Some weapons were made with duraluminum receivers with special barrels and, like the Model 9, a great number of presentation finished pistols were manufactured.

It is interesting that the Model PP can be fired in a similar manner to a double action revolver. A steel block allows the weapon to be carried with a round in the chamber and the hammer down in complete safety, and when needed, the trigger is pulled and the gun fired double action. From the first shot onward the gun works as a normal automatic pistol.