The MP5 is the first version and also the standard version of the MP5 family. Early versions use a slimline handguard, while all later versions use the wider tropical handguard. Until 1977 straight 30 round magazines were used, since then 15 and 30 round curved magazines are standard.

MP5A2: MP5 with fixed polymer stock.
MP5A3: MP5 with retractable stock.
MP5A4: MP5A2 with burst fire trigger group.
MP5A5: MP5A3 with burst fire trigger group.
MP5SF2: Semi-automatic MP5 with fixed polymer stock.
MP5SF3: Semi-automatic MP5 with retractable stock.

The MP5SD is a version of the MP5 with integrated silencer. The SD suffix stands for Schalldämpfer, which is German for silencer. Unlike most silenced firearms the MP5SD is not designed to use subsonic ammunition. The silencer slows standard ammunition down to subsonic speeds.

MP5SD1: Uncommon model that is not fitted with a stock.
MP5SD2: Fixed polymer stock model of the MP5SD.
MP5SD3: Retractable stock model of the MP5SD.
MP5SD4: MP5SD1 with burst fire trigger group.
MP5SD5: MP5SD2 with burst fire trigger group.
MP5SD6: MP5SD3 with burst fire trigger group.

The MP5-K is the Kurz, German for compact, version of the MP5. The MP5-K model differs from the original MP5 in having a shorter barrel, shortened receiver and no stock. The shorter receiver houses a lighter bolt, resulting in a higher rate of fire. Due to the shorter forearm a vertical grip is installed to hold the weapon. The baseline MP5-K is fitted with diopter sights. Low profile fixed sights are fitted on the MP5-KA1 and reduce snagging when drawing a concealed MP5-K. The KA4 and KA5 models are MP5-K and A1 models with a burst fire trigger group. The MP5-KN is the Navy model has an ambidextrous trigger group and longer barrel with three suppressor attachment lugs. The latest model is the MP5-K PDW, which is fitted with a side folding stock. PDW stands for Personal Defense Weapon. Recently the MP5-K PDW is also sold with the side folding stock of the UMP.

A legendary model of the MP5 is the Heckler & Koch MP5-K suitcase. This is a suitcase in which a MP5-K is fitted attached to an intricate firing mechanism. The MP5-K can be fired from the suitcase by pulling a trigger in the carry handle. The proper technique for using the suitcase is to hold it against your chest with both hands. There is no way of aiming the suitcase, except for gut feeling. Therefore a lot of training is needed.

All versions of the MP5 family are chambered in the 9x19mm round, except for the MP5/10 and MP5/40. These models are normal MP5's but chambered in the 10x25mm and .40 S&W round respectively. The MP5/10 uses translucent orange or gray straight 30 round magazines. The MP5/40 was issued with straight grey translucent and aluminum 30 round magazines. The A2 models have a fixed stock, with the A3 models having a retractable stock. The A4 and A5 models are A2 and A3 models with a burst fire trigger group. Due to excessive recoil two or three round burst trigger groups are present on most of these larger caliber MP5's.