This study was conducted by utilizing an experimental handwriting intervention using eight critical features as identified by Reutzel et al. (2019). The intervention used lower-case letters to group letters with similar features for instruction for preschool-age children. These features were used to facilitate instruction with letter-writing fluency, letter-writing quality, letter names and letter sounds in a pre-K (3-4 years of age) classroom. The critical features of letters include short and long lines, short and long hooks closed and open curves, and a U-turn/hump and dot. This study examined the impact of a handwriting intervention using critical features on acquisition of letter names, letter sounds, phonemic awareness, and handwriting fluency and quality. This study included 29 pre-K students in private school settings, randomly assigned to form an experimental and a control group for each center. The intervention lasted 8 weeks, at 30-minute sessions per group. Small group instruction of the handwriting intervention took place in both centers with the experimental group. There were 2 small groups, n = 29, 15 in the experimental group and 14 in the control group. Quantitative data collection consisted of data from the pre-and post-handwriting analysis and FastBridge assessments for letter recognition and letter sounds. At posttest, ANCOVA analyses demonstrated statistically significant differences between the intervention group and control group on all measures (i.e., phonological awareness, handwriting quality, handwriting fluency, letter names, and letter sounds). [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]