Singapore came in second in the 2016 Progress in International Reading Literacy Study (PIRLS), just behind Russia.
The grade 4 students in Singapore reported improved scores in reading, by jumping two spots up from the 2011 ranking.
Out of the 50 countries that were assessed, Russia moved up to the number one spot with an average score of 581, while Singapore came in second with a score of 576.
The top five countries include: Russia, Singapore, Hong Kong, Ireland and Finland.
The PIRLS assessment, which has been running since 2001, follows a five-year cycle. It involves nine and 10-year-olds from grade 4 or year 5 completing comprehension tests and provides international comparative data on how well children read in different countries.
The study, which is run by the International Association for the Evaluation of Educational Achievement (IEA) in Amsterdam, and Boston College, USA, tested more than 319,000 students in 50 countries.
PIRLS also involves questions for head teachers, class teachers and students and a survey for parents and caregivers.