There is an absence of cross-cultural qualitative research exploring sociocultural factors affecting reading motivation. To address the gap, the present study adopted the Bronfenbrenner's bioecological model of human development to investigate factors impacting reading motivation across American and Japanese fourth grade students. Additionally, we aimed to identify ways to motivate both students to read. Semi-structured interviews for 12 students in each country were conducted. Our study identified a consistent pattern in which the reading motivation of both American and Japanese students was directly influenced by the "microsystem." Our findings also suggest distinct patterns between American and Japanese students. While American students exhibited a direct impact from the "microsystem," Japanese students' reading motivation was influenced by several systems, including the "microsystem," "exosystem," and "macrosystem." We explained that the observed unique patterns between American and Japanese students could be due to cultural differences. We identified several effective ways to motivate students to read.