The invention relates to anti-±2 integrin antibodies and their uses. Humanized antibodies are disclosed that bind to the I domain of ±2 integrin and inhibit the interaction of ±2²1 integrin with collagen. Also disclosed are therapeutic uses of anti-±2 integrin antibodies in treating ±2²1-mediated disorders, including anti-±2 integrin antibodies that bind to ±2 integrin without activating platelets.