This study surveyed 183 college and senior high school students' graph-interpretation competence in scientific and daily contexts. Specifically, whether students' graph interpretation in scientific and daily contexts differed across educational levels was investigated. Furthermore, the questions of whether students' graph interpretation competence in scientific contexts might predict their graph interpretation in daily contexts were explored. Other factors including age and gender were also considered and examined to discern significant factor(s) predicting graph interpretation competence in daily contexts. Results indicated that there were statistically significant differences across educational levels in terms of graph interpretation competence in both scientific and daily contexts. Furthermore, the students' graph interpretation competence was related between scientific and daily contexts. The important factors predicting students' graph interpretation in daily contexts include age and graph-interpretation in scientific literacy. Implications are discussed.