Savings and investment are crucial economic factors that have long attracted the attention of scholars who focus on all aspects related to them. These two variables are key drivers of economic growth and contribute significantly to a nation’s wealth. This study examines the impact of savings and investment and quality of life on Oman’s national economy, as well as the effect of family size on the savings and investment of working citizens in North Sharqiyah (NS). A questionnaire survey was used to collect data, with a sample of 260 respondents from seven wilayats in NS. Data analysis was conducted using the SPSS and PLS-SEM software. The findings reveal that 40.8% of NS citizens lack awareness of investment patterns and also show a significant relationship between savings, investment, and the national economy. Additionally, we tested the moderating effect of family size on investment and QoL. It has a negative impact on investment. The results show that increasing family size reduces investment and affects the economy later. The results emphasize the importance of savings and investment in enhancing both the economy and quality of life. The study recommends promoting savings and investment; authorities such as the Capital Market Authority and Muscat Stock Exchange, the North Sharqiyah governorate, and HEIs should increase awareness, as this would contribute to the country’s economic prosperity and individual financial security.