On April 21st 2015 Google began ranking mobile-friendly websites and Apps higher in search results than websites which are not.
Google’s statement: Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high quality search results that are optimized for their devices.
A responsive (mobile-friendly) website would have the following features:
• Is responsive to different screen sizes
• Properly configured
• Able to be viewed on multiple device types
If you are worried your website may not have these features there are many tools available on the web for you to check.
Google has a mobile friendly test, if you click the image below it will take you to the test.