When the Swedish Military decided to procure the German-built Leopard Improved (Strv 122), they decided to also lease Leopard 2A4 tanks from Germany as part of the deal. 160 Leopard 2A4s were delivered in 1994, with the stipulation that they would be returned after 15 years. The Bundeswehr was willing to loan out their tanks because of the requirement that they reduce the amount of military equipment in service, due to the end of the Cold War.

The Swedish Leopard 2A4s were designated as the Stridsvagn (Strv) 121. They came from various production series - known as losung - from losung 1 (built in 1979) to losung 5 (built in 1987). As such, there were some minor external variations among the Strv 121 tanks.