As an integral part of education, Physical education develops man physically, mentally, socially, emotionally and intellectually sounds in meeting a day’s work productively. Most schools in the area under studying are usually filled to the brim which calls for urgent intervention. This study, therefore, examined influence of Environmental Serenity and Sound Knowledge of Physical Education Teachers in Government Secondary Schools in Ilorin East, Kwara State. The study determined whether school climatic condition; availability of school sports facilities and overpopulated classroom predicting sound knowledge in physical education teachers in government secondary schools in Ilorin East, Kwara State. A descriptive research design of the survey method was used and the population of the study was one thousand two hundred and sixteen (1,216) Students in Ilorin East, Kwara State. Purposive sampling technique was used with the help of the research advisor to select three hundred and fifty (350) respondents from the total population. The researchers – developed instrument was employed and validated. Tests and retest method was used to measure the reliability and 0.76 coefficient was obtained. The instrument was administered, the data collected was subjected to statistical analyzes using frequency and percentages to answer research questions and chi-square was employed to examine the three formulated null hypotheses at 0.05 level of significance. The findings from the study were that; school climate significantly influence environmental serenity and sound knowledge of physical education teachers in government secondary schools in Ilorin East, Kwara State with the X2 value of 304.6 > Critical table value of 21.03 with 12 degree of freedom @ 0.05 level of significance; availability of sports facilities and equipment significantly influence environmental serenity and sound knowledge of physical education teachers in government secondary schools in Ilorin East, Kwara State, with the X2 value of 74.9 > Critical table value of 21.03 with 12 degree of freedom @ 0.05 level of significance; overpopulated classroom significantly influence environmental serenity and sound knowledge of physical education teachers in government secondary schools in Ilorin East, Kwara State, with the X2 value of 397.6 > Critical table value of 21.03 with 12 degree of freedom @ 0.05 level of significance. The study concluded based on the findings, that school climate, availabilities of sports facilities and equipment, overpopulated classroom are challenges to the sound knowledge of physical education in government secondary schools in Ilorin East, Kwara State. However, the study  recommended that, teachers should ensure that physical education classes are done in a conducive and favourable climate condition, The government and public, private partnership and other stakeholders in the field should established thorough visibility study before situating schools setting as teaching and learning of physical education is enhanced either negatively or positively based on atmospheric condition and Adequate facilities and equipment should be provided to enhance the sound and healthy knowledge of physical education, The government and stakeholders should ensure that appropriate numbers of students are in a class to ensuring that effective teaching is carried out in a serene environment