As you are using Selenium 3.8.0Selenium 3.8.0 you have to use GeckoDriver mandatorilyGeckoDriver as a mandatory. But again as you are using Firefox v46.0Firefox v46.0 you have to set the capability marionettemarionette toas FalseFalse through DesiredCapabilities()DesiredCapabilities() as follows :
from selenium import webdriver from selenium.webdriver.common.desired_capabilities import DesiredCapabilities cap = DesiredCapabilities().FIREFOX cap["marionette"] = False browser = webdriver.Firefox(capabilities=cap, executable_path="C:\\path\\to\\geckodriver.exe") browser.get('http://google.com/') browser.quit()