The research aims to explore secondary school students' digital media usages, to explain model of students' digital citizenship and to explain influence of digital media uniqueness, students' political motivation and digital media usages on their digital citizenship. The survey research used questionnaire to collect data from 820 sample from secondary school students nationwide. The survey results indicate that sample mostly use Face Book, Youtube and Instagram. They frequently use such media every hours in a day. They rarely use digital media for political purpose but mostly for entertainment, following movie stars pages, chatting and information searching. However, they use the digital media more often for setting up group conversation, seeking for goods, surveillance and show their identity via social media post. They highly accepted uniqueness of digital media as platform that provides public sphere, allow diffusion of large information, serves as user connection and allow user to generate their owned content. Regarding to sample's political motivation, they indicate their motivation from their interest in national political situation, expectation of Thailand to be democratic country and their learning experience on politic subject. The result of confirmatory factor analysis of students' digital citizenship are as Model Chi-Square, p-value .00, CMIN/DF = 2.59, RMSEA = 0.04, GFI = 0.91 and CFI = 0.92. The measurement model of students' digital citizenship comprised of 6 factors. These are 1) Right and responsibility (factor weight = 0 .9 4 , R² = 0 .88 ) 2) Respect self and others (factor weight = 0.92, R²= 0.85) 3) Educating self and others on digital usage (factor weight = 0.92, R²= 0.85) 4) Value and ethic (factor weight = 0.90, R² = 0.81) 5) Protecting self and others (factor weight = 0.88, R²= 0.77) 6) Democracy fundamental (factor weight = 0.78, R²= 0.60) The stepwise multi-regression analysis result indicate that the uniqueness of digital media (β = .307) digital media uses on social purpose (β = .259) political motivation (β = .234) and digital media uses on political purpose (β = -.117) have influent on students' digital citizenship (R2 = 0.361). The ANOVA and LSD analysis as .05 statistical significant level, reveal that student who gained GPAX 3.51 – 4.00 obtain higher level of digital citizenship than others. The students who participated in social contribution activity 3-4 times a year have higher level of digital citizenship than those who participated 1-2 times a year or those who never participated.
