This study aims to determine the effects of different levels of water salinity on the growth and yield of three rice varieties. The experiment was conducted on an open field from January to May 2020. The experiment design used 4x3 factorial in Completely Randomized Design (CRD) with three replications. Factor A treatments were four levels of water salinity: 0 (control), 5, 10, and 15 dS/m. Factor B treatments were three rice varieties, of which two were Thai namely Chai Nat 1 (CNT 1) and Pathum Thani 1 (PTT 1) and the other was a salt-tolerance variety from Indonesia; Inpari-35 (IN 35). The results showed that increased water salinity level could decrease all yield and yield components, both assessed from average means and percent reduced values as compared with 0 dS/m (control). The number of fertile tillers, the percentage of filled grain, and the yield per plant are severely affected by the salinity stress from 5 dS/m onward. Thai rice varieties (CNT 1 and PTT 1) showed higher reduction values in all parameters (excepted 1000 seed weight) as compared with Inpari 35. Although both CNT 1 and PTT 1 varieties showed different susceptibility to water salinity levels on different yield components, PTT 1 was more adversely affected at all water salinity stress levels, especially on the number of fertile tillers, filled grain percent, and yield per plant.