Flexible light-emitting devices that can transform from two-dimensional to three-dimensional (3D) forms could be of use in the development of next-generation displays. Various approaches for converting two-dimensional structures into 3D architectures have been explored, including origami methods that rely on folding along lines in which a structure has been thinned. But the fabrication of foldable 3D light-emitting devices remains challenging due, in particular, to the lack of a practical method for patterning the folding lines. Here we show that 3D foldable quantum dot light-emitting diodes (QLEDs) can be created using laser patterning and metal etch-stop layers with customized ablation thresholds. The approach allows etching to be limited to selected layers of the multilayered QLEDs, and it can be precisely tuned by using alloy-type etch-stop layers. The approach can be used to create QLED architectures with extremely small bending radii (0.047 mm), and we illustrate its capabilities by fabricating a 3D foldable passive matrix array of QLEDs that can display letters and numbers. Two-dimensional arrays of quantum dot light-emitting diodes can be folded into three-dimensional architectures-including a passive matrix array that can display letters and numbers-by using laser patterning and metal etch-stop layers to create folding lines.