PurposeTo estimate k‐space trajectory errors in non‐Cartesian acquisitions and reconstruct distortion‐free images, without trajectory measurements or gradient calibrations.Theory and MethodsThe Trajectory Auto‐Corrected image Reconstruction method jointly estimates k‐space trajectory errors and images, based on SENSE and SPIRiT parallel imaging reconstruction. The underlying idea is that parallel imaging and oversampling in the center of k‐space provides data redundancy that can be exploited to simultaneously reconstruct images and correct trajectory errors. Trajectory errors are represented as weighted sums of trajectory‐dependent error basis functions, the coefficients of which are estimated using gradient‐based optimization.ResultsTrajectory Auto‐Corrected image Reconstruction was applied to reconstruct images and errors in golden angle radial, center‐out radial, and spiral in vivo 7 Tesla brain acquisitions in five subjects. Compared to reconstructions using nominal trajectories, Trajectory auto‐corrected image reconstructions contained considerably less blurring and streaking and were of similar quality to images reconstructed using measured k‐space trajectories in the center‐out radial and spiral cases. Reconstruction cost function reductions and improvements in normalized image gradient squared were also similar to those for images reconstructed using measured trajectories.ConclusionTrajectory Auto‐Corrected image Reconstruction enables non‐Cartesian image reconstructions free from trajectory errors without the need for separate gradient calibrations or trajectory measurements. Magn Reson Med 76:757–768, 2016. © 2015 Wiley Periodicals, Inc.