Gas sensor (2) for measuring properties of a gas (1), including a gas viscosity sensor (4) comprising a gas interface portion (20) in contact with the gas (1) to be measured, and a measuring chamber system (15) comprising a measuring chamber(16), a first resistive passage (18) fluidically connecting the measuring chamber (16) to the gas interface portion (20), a pressure generator (25) configured to generate a change in pressure in the measuring chamber, and a pressure sensor (28) configured to measure a time dependent variation in pressure of gas in the measuring chamber, the time dependent variation of pressure in the measuring chamber due to flow of gas through the resistive passage being correlated to a viscosity of the gas. The gas viscosity sensor further comprises a reference chamber system (21) comprising a reference chamber and a second resistive passage (24) fluidically interconnecting the reference chamber (22) to the gas interface portion (20), the reference chamber (22) being coupled to the pressure sensor (28) of the measuring chamber such that the pressure sensor is configured to measure a differential pressure between a pressure in the measuring chamber and a pressure in the reference chamber.