Background: Oral hygiene practice includes all the processes for keeping mouth clean and healthy. Good oral hygiene practice is necessary for prevention of bad breath, dental caries, and periodontal disease. Objective: To assess prevalence of oral hygiene practice and associated factors among grade 5-8 school children in Dabat district, Amhara Region, North West Ethiopia. Methods: A school based cross-sectional study was conducted among 799 school children’s in Dabat district. Data were collected by trained data collectors by using pretested questionnaire. Data were entered to Epi-data version 4.6 and exported to SPSS version 25.0 for data cleaning and analysis. Bi-variable and multivariable logistic regressions were employed to identify factors associated with oral hygiene practice. Result: A total of 799 students, were included in the study with a response rate of 100%. From the total participants, 455 (55.7%) were females. About 62.7% of the participants were included in the age interval of 10-14 years. There were 51.2% of respondents who had good practices on oral hygiene. It was observed that statistically significant association was found between oral hygiene practices and respondents who had educated father (AOR=1.93: 95% CI, 1.36, 2.75: P= 0.00), female respondents (AOR=1.52: 95% CI, 1.14, 2.04: P= 0.005) and urban Residence of respondents (AOR=1.70: 95% CI, 1.16, 2.47: P= 0.007). There was no significant association between oral hygiene practices and family size, marital status of parents, and occupation of mothers (P > 0.05). Oral hygiene practices are significantly associated with positive attitude toward oral hygiene among primary school children of North West Ethiopia Dabat district, (AOR=1.70: 95% CI, 1.21, 2.27: P =0.002). Conclusion: The present study revealed that male, rural residents, uneducated respondent father and the participants with a poor attitude were associated with poor oral hygiene practice. So Long-term school based oral health education program is highly recommended. Keywords: Oral hygiene practices, associated factors, primary school children