A flat‐crystal spectrometer for analyzing ultrasoft x rays in the wavelength region 10–25 A˚ was constructed for use on an electron beam ion trap. The spectrometer employs a position‐sensitive proportional counter for detection and affords a nominal resolving power of 2000 at a Bragg angle of 45°. Measurements of theL‐shell spectra of Ne‐like Fe16+and of the 3s1/2–3p3/2transitions in near Na‐like Pb71+, which fall into the wavelength region from 13.5 to 17.5 A˚, are presented demonstrating high throughput and excellent signal‐to‐noise characteristics. The actual resolving power achieved was limited by the intrinsic resolution of the crystal to 500. A resolving power close to the nominal value was achieved in second order Bragg reflection.