This study aimed to examine and analyze the effect of word of mouth on the purchasing decisions of consu-mers of all-you-can-eat Japanese restaurants. The type of research was causal quantitative analysis tested using a linear regression test. The sampling technique was purposive sampling. The samples were 100 all-you-can-eat Japanese res¬tau¬rants con¬sumers in Surabaya, Indonesia. The re¬sults showed that word of mouth had a positive and significant influence on purchasing decisions. It was a new study. Thus, this research could help manage the restaurant bu¬siness, thereby improving the existing marketing perform¬ance.