In recent years with the increasingly world-wide introduction of the Internet, the use of online questionnaires has increased dramatically. However in Thailand, there has been only very limited systematic research on web-based design in Thailand, including for Thai undergraduates who are the biggest group of Thai internet users. The particular characteristics of the Thai language (e.g. no capital letters, no break between words, Thai script etc.) present some interesting challenges for online Thai surveys. This experimental study investigated web-based survey design principles based on an English language background trial at a Thai university with individual interviews and focus groups with the use of think aloud and other research techniques. The findings of two types of web usability tests revealed that the scrolling web-based format was the most suitable for conducting surveys and that such surveys are most likely to attract higher response rates when endorsed by a trusted organization, when instructions are short, simple and specific, when closed and dichotomous questions provide sufficient answer options and when matrix and semantic differential questions are limited. Research also indicates that the font, Ms Sans Serif of size