Flexible and stretchable nanostructures have broad technological applications. Although nanostructures synthesized with metallic glasses, the alloys being of amorphous atomic structure, exhibit superior properties, they are typically too rigid to be used as flexible materials with existing synthesis techniques. In this study we report periodic and crumpled metallic glass nanostructures that can accommodate a large amount of stretching. We demonstrate that their morphologies and characteristic length scale can be well controlled, and that feature sizes as small as ∼200 nm can be readily achieved. With their integrity maintained, the nanostructures can be stretched to a strain of ∼100%, leading to broadly tunable properties. The approach is not limited to specific metallic glasses, but is applicable to a wide range of glass-forming alloys. This not only enables metallic glasses to be used under extreme stretching conditions, but also helps in the exploration of new functionalities of glassy materials.