Monopiles used as foundations for offshore wind turbines are widely installed into the seabed by impact driving. This study examines the impact of hammering on the subsequent horizontal response of 1/100 scale monopile model by using a large-beam geotechnical centrifuge. A special device including small-scale hammer was designed to install monopiles with 50 mm in diameter to an embedment depth of 250 mm in flight, and then to apply lateral loading on the monopile head without stopping the centrifuge. Tests findings from two horizontal loadings are discussed, with the monopile either Jacked monotonically at 1g or impact driven at 100g. The results highlight the need to consider the impact of installation on the horizontal monopile response.