The purpose of this study was to identify the behavior of Thai teenagers using
smart phones which affected itself and society. The samples of the study consisted of
teenagers between the ages of 16-26 years old using smart phones in Bangkok. The data
were analyzed through descriptive statistics comprising percentage, frequency and
standard deviation (S.D.) by using SPSS. The questionnaire was used as a data collection
instrument. The results showed that the majority of respondents were male whose ages
were between 21-22 years old, high school students and university students with monthly
incomes of 6,001-10,000 baht. The respondents often used their smart phones from 5.01
p.m. to 9.00 p.m. Places where the respondents used their phones were their homes with
the use of more than 30 times per day. The study revealed that teenagers used smart
phones to communicate with their friends 6-7 minutes per day through Facebook
application. The negative effect resulted by using smart phones was to become addicted to
games. The decreasing relationship among the society was that people had less oral
communication.