This study portrays the relationship between Radon activity concentration and physicochemical parameters in groundwater in Erbil city, Iraq. Primary data of groundwater samples were collected from five different zones in Erbil, during February 2019. Water samples were collected for both Radon measurement and physicochemical analysis. Water samples were taken from 24 different wells as a reference, then directly measured their radioactivity at the laboratory of Erbil Environment Office. Dissolved Radon 222 Rn in a sampled groundwater has been measured using an electronic Radon detector RAD 7. Determination of various parameters such as pH, total dissolved solids, total hardness, Sulfate, and Magnesium in groundwater has also been measured. Moreover, regression analysis illustrated that there is no significant relationship observed between pH, TDS, and hardness, Sulfate, and Magnesium with Radon activity concentration because these are no significant at the 95% confidence level. Otherwise, the correlation of determinate (R 2 ) values show the relationship between Sulfate and Magnesium with Radon concentration because these are significant at the 95% confidence level. All measurements were done in almost identical environmental conditions to avoid the minor differences in meteorological parameters.