Khao‐tan is a popular Thai traditional glutinous rice snack that involves a deep frying process. Nowadays, consumers are concerned about the safety of fried food and its potential to contribute to obesity. Puffing using a home microwave oven is an alternative that is more convenient, requires a shorter processing time, has a lower cost, is healthy and environment‐friendly. This research investigated the optimal processing conditions (initial moisture content [IMC], microwave power [MWP], and puffing time [PT]) to puff khao‐tan from three rice varieties (sticky rice [SR], rice berry [RB], and black rice [BR]) using the microwave. Response surface methodology (the Box–Behnken technique) was applied. The process responses comprised puffing yield, expansion ratio, hardness, and yellowness. The results indicated that the optimized conditions for khao‐tan were 10% IMC, 1,200 W MWP, and 25 s PT with overall desirability values of 0.733, 0.642, and 0.899 for SR, RB, and BR, respectively. Practical applications Recently, microwaves have become popular use in the food industry. This study provides a good technique to introduce microwave technology in the snack industry to puff a Thai traditional rice snack, namely, khao‐tan using a home microwave oven. The optimized conditions can help with puffing khao‐tan made with three varieties of rice (sticky rice, rice berry, and black rice) to achieve consumer acceptance in terms of product quality and a healthy product. This work can be applied commercially and on a small scale.