In an attempt to evaluate the outdoor environmental health awareness programme effects on children's knowledge, attitudes, and behaviours toward their environment in Gaza Strip-Palestine, the researcher utilized quantitative and qualitative measures by incorporating observations of children's engagement in Program activities as well as conducting a focus group discussion with the children. Pre- and post-tests self-reported questionnaire were also applied to assess the effectiveness of the outdoor environmental health awareness programme implemented for the 4th, 5th, and 6th grades of a children's primary school in an after-school setting in Gaza Strip. The results indicated positive shifts in knowledge and change in environmental attitude and behaviours. It was found that the study results showed differences in the level of KABs among the experimental children, attributed to socio demographic variables such as (gender, age, type of study, children parents' job, monthly income, educational back ground of children's parents, and residential area), with remarkable differences and variations in reaching significantly within all these variables whether in pre or post test.