iPhone 5 not ringing for all calls

ok check your do not disturb settings (see if there is a moon icon displayed beside your battery icon) if so, go to settings>Do not disturb and turn it off.

I suspect one of two possible causes:

1. Settings > Do Not Disturb may be "On".
2. The people phoning you when the ringing fails may have custom ringtones set up in Contacts.

check your do not disturb settings, may be you allowed repeated calls ,allowed calls from your favorites or silence only while iphone is locked

Just got back from the Verizon store because my iPhone suddenly stopped ringing or alerting me to emails (though it did continue to vibrate). I checked online and saw lots of folks with the same problem, with solutions including rebooting, making sure the Do Not Call settings were correct and resetting your Settings. None of these worked for me.
However, it took the Verizon greeter about 5 secondsto diagnose/fix the problem - I was completely unaware that there is a Ringer/Mute Switch - it's a toggle switch on the left side of the phone above the volume buttons that lets you put the iPhone into silent mode, for when you want to receive calls but not hear the phone ring. If you see orange, the switch is to the left and you're in Ringer Mute mode; click to the right and the problem goes away. Simple solution to a major annoyance.

I know the mute button. Definitely not my problem. I turned the phone off and on again, soft reset and went through the whole trobleshooting process. Nothing! It vibrates but no ring

Hello friends.

Follow the link. To make ringer on.

http://macnancy.wordpress.com/2013/01/16/why-wont-my-iphone-5-ring/

nice going. just got phone replaced yesterday and didn't have a clue hot to get the phone to make a sound. I saw that button, but your post made it happen. thank you sir.

Thank you. That is exactly what was wrong with mine.