In this paper, I seek to evaluate gas leakage detection and monitoring based on a microcontroller and Internet of Things (IoT) technology. The project involves using a combustible gas sensor (MQ2) in order to detect the presence of liquefied petroleum gas (LPG), smoke, and carbon monoxide gas (CO). The MQ2 gas sensor will detect the concentration of the gas according to the voltage output of the sensor, the ESP8266 will send the data reading from the gas sensor to an OLED monitor, and to the Blynk IoT platform over an IOS phone; the data visualization is done using Blynk IoT platform. The results of the studies show that the amount of gas leakage that can be detected depends on the distance between the point of leakage and the gas sensor and the concentration of the gas.