This study was to assess the attitude of hand washing behaviour among school children otherwise known as pupils with special reference to Kaduna State in Northern Nigeria. The study employed the ex-post factor Research design. The population comprises of all public and private primary school pupils in Kaduna state which give a total of one million two hundred and ninety-three thousand six hundred and twenty-six (1,293,526). Stratified random sampling technique was used to stratified the state in three senatorial districts and two local governments from each senatorial district were selected using simple random sampling while proportional sampling was used in selecting the respondents. Sample of seven hundred and sixty (760) copies of the questionnaire was used for data analysis. The frequencies and sample percentage were used for the demographic characteristics of the respondents while descriptive statistics which comprises of mean and standard deviation were used for the research questions answered. The formulated hypotheses analysed was inferential statistics t-test statistics and were tested at 0.05 alpha level of significance. The findings revealed that the attitude of hand washing behaviour among primary school pupils was significant. It was recommended that the school authority should further encourage the improvement of the attitude of primary school pupils towards hand washing after visiting the toilet, before and after eating or and their normal activities through further enlightenment programmes.