First and second graders who were good and poor handwriters completed three writing tasks: writing letters of alphabet in order from memory, letter copying in a passage, and composing on provided topics. A coding scheme was used to evaluate these dimensions of legibility: spacing between words and between letters within words, alignment (letter placement on lines), letter height, letter slant, reversals, added strokes, missing strokes, and missing letters. Although results were somewhat task dependent, most differences between good and poor handwriters involved poor handwriters generating more letters with added strokes, producing smaller letters, and exhibiting more variability in spacing and alignment. The good and poor handwriters did not differ on average performance in alignment of words on the baseline or in spacing of letters within words and spacing between words. Each of three dimensions of handwriting contributed uniquely to the handwriting of first and second graders: motor programs, visual-spatial arrangement on the written page, and letter formation parameter setting.