The purpose of the study is to determine how web usability and interface design on webpage development can affect the purchasing decision of consumers of group buying websites. With the rise of ecommerce, entrepreneurs nowadays cannot assume that when they build a website, customers will automatically visit them. Industry analysis show how companies can earn decreased potential sales and low gains on return of investment (ROI) due to poor usability and errant designs. The researchers aimed to conduct an assessment on the current performance of websites in online group buying, identify significant factors that will affect the decision of webpage designs, create an ideal generic webpage layout for group buying websites, and evaluate the formulated webpage layout based on the assessment of current group buying websites. The methodology includes distribution of survey questionnaire and usability test among respondents. ANOVA and t-test were used as the statistical treatment of data. The study was able to verify through the comparison of usability tests that the proposed website showed significant improvements to improve the webpage in terms of web usability and interface design. The findings will be useful to entrepreneurs, online shoppers and future researchers for an improved e-commerce experience.