Compositions and methods comprising polynucleotides and polypeptides having glyphosate-N-acetyltransferase (GLYAT) activity are provided. In specific embodiments, the sequence has an improved property, such as, but not limited to, an improved specificity for glyphosate when compared to an appropriate control resulting in decreased off target acetylation of, e.g. an amino acid such as aspartate. Further provided are nucleic acid constructs, plants, plant cells, explants, seeds and grain having the GLYAT sequences. Various methods of employing the GLYAT sequences are provided. Such methods include methods for producing a glyphosate tolerant plant, plant cell, explant or seed and methods of controlling weeds in a field containing a crop employing the plants and/or seeds disclosed herein.