Objectives: This study aimed to identify agreement between smartphone addiction(SA) and perceived SA among adolescents. Methods: This survey was done with 394 subjects conveniently sampled from elementary school (ES), middle school (MS), academic (AHS) and vocational (VHS) high school. The data were collected from June 20 to July 20, 2013 with self-administered questionnaire and analyzed by descriptive statistics, chi-square test and Cohen’s kappa (κ). Results: High risk of SA showed 2.8% in total, 1.0% in ES, 2.1% in MS, 4.1% inAHS, and 4.0% in VHS, which was statistically different by type of school (p<0.001). Perceived SA showed 22.6% in total, 9.0% in ES, 21.9% in MS, 33.7% in AHS, and26.0% in VHS, which was statistically different by type of school (p=0.003). Theagreement between SA and perceived SA was 82.0% (κ=0.54) in total, 91.8% (κ=0.53)in ES, 75.0% (κ=0.33) in MS, 77.5% (κ=0.53) in AHS, and 84.8% (κ=0.65) in VHS. Conclusion: The agreement between SA and perceived SA showed moderate in general, but fair in MS. It is suggested to develop step-by-step activities to reduce the gapbetween SA and perceived SA among adolescen, in particular, middle school students.