question: Variants of concern (VOCs) of severe acute respiratory syndrome coronavirus type-2 (SARS-CoV-2) threaten the global response to the COVID-19 pandemic. The alpha (B.1.1.7) variant appeared in the UK became dominant in Europe and North America in early 2021. The Spike glycoprotein of alpha has acquired a number mutations including the P681H mutation in the polybasic cleavage site that has been suggested to enhance Spike cleavage. Here, we show that the alpha Spike protein confers a level of resistance to the effects of interferon-{beta} (IFN{beta}) in lung epithelial cells. This correlates with resistance to restriction mediated by interferon-induced transmembrane protein-2 (IFITM2) and a pronounced infection enhancement by IFITM3. Furthermore, the P681H mutation is necessary for comparative resistance to IFN{beta} in a molecularly cloned SARS-CoV-2 encoding alpha Spike. Overall, we suggest that in addition to adaptive immune escape, mutations associated with VOCs also confer replication advantage through adaptation to resist innate immunity.