<p>A meteorological drought is an unusually long period without rainfall that causes problems in nature and for humans. This study compared four meteorological drought indices: the Standardized Precipitation Index (SPI), the Percent of Normal Precipitation Index (PN), the Decile Index (DI), and the Rainfall Anomaly Index (RAI) computed for the annual (12-month) rainfall time series. The four indices were calculated for eight rainfall stations in the Mae Klong River Basin, Thailand during 1971–2015. Comparison between the drought indices was done using Pearson’s correlation coefficient (r) and Cohen’s Kappa test. The correlation coefficient between the four drought indices varied from 0.948 to 1. The values of the unweighted Cohen’s Kappa ranged from 0.104 (‘Slight’ agreement) to 1 (‘Almost perfect’ agreement) while the weighted Cohen’s Kappa varied from 0.215 (‘Fair’ agreement) to 1 (‘Almost perfect’ agreement) between the indices for all the stations. For the whole Mae Klong River Basin, the Cohen’s Kappa test indicated a lesser degree of agreement (fair to moderate) between the majority of the drought indices pairs, despite the generally very high correlation coefficient values (0.977 ≤ r ≤ 1). The results indicated that the Cohen’s Kappa test can be more effective in determining the strength of agreement or disagreement between the drought indices as compared to the correlation analysis. The Mann–Kendall test was used to calculate the trends in the drought indices while the magnitude of the trends was determined by the Sen’s slope test. All the four drought indices showed statistically non-significant increasing trends for the mean annual rainfall in the basin.</p>