Science and Education Publishing American Journal of Educational Research 2327-6150 3 2 2015 02 11 The Effect of Smartphone on Students' Critical Thinking Skill in Relation to the Concept of Biodiversity 243 249 EN Vandalita M.M. Rambitan Biologi Education, Faculty of Teacher and Training Education, Mulawarman University of Samarinda EDUCATION20153218 10.12691/education-3-2-18 2015 01 28 2015 02 05 2015 02 11 The advance in technology and communication currently has significantly influenced the development in the field of education, including the use of smartphones that can be adopted as a source of learning in schools. The current study was conducted to investigate the effect of smartphones on students' critical thinking skill in relation to the concept of biodiversity. The population of the study was all year-11 students of Senior High School 5 Samarinda, while the sample was the science-program class XI 2 (learning with Smartphone) and XI 3 (learning without smartphones) with 25 students for each class. The obtained data were analyzed with t test and the obtained value of tcalculation = 4.30 and ttabulation = 2.01. The result of the data analysis showed that the value of tcalculation > ttabulation at the significance level 0.05, so it is concluded that learning with smartphones has the effect on students' critical thinking skill in relation to the concept of biodiversity.