A compact laser synchrotron source (LSS) is proposed as a means of generating tunable, narrow bandwidth, ultra‐short pulses of hard x rays. The LSS is based on the Thomson backscattering of intense laser radiation from a counterstreaming electron beam. Advances in both compact ultra‐intense solid‐state lasers and high brightness electron accelerators make the LSS an attractive compact source of high brightness pulsed x rays, particularly at photon energies beyond ∼30 keV. The x‐ray wavelength is &lgr;[A˚]=650 &lgr;0[&mgr;m]/Eb2[MeV], where &lgr;0is the laser wavelength andEbis the electron beam energy. ForEb=72 MeV and &lgr;0=1 &mgr;m, x rays at &lgr;=0.12 A˚ (100 keV) are generated. The spectral flux, brightness, bandwidth, and pulse structure are analyzed. In the absence of filtering, the spectral bandwidth in the LSS is typically ≲1% and is limited by electron beam emittance and energy spread. Two configurations of the LSS are discussed, one providing high peak power and the other moderate average power x rays. Using present day technology, the LSS can generate picosecond pulses of x rays consisting of ≳109photons/pulse with a peak brightness of ≳1020photons/s mm2 mrad2(0.1% BW) and photon energies ranging from 50 to 1200 keV.