Apple - typing a backtick on Mac OS X Snow Leopard

Disclaimer: This info is for English keyboards. If you're using a keyboard for a different language, look for the keys on your keyboard that match the photos. Pictures of Apple's keyboards for various languages can be found here.

This question was answered 5 years ago, but pictures may be helpful for viewers coming upon it now.

To make a backtick on the US English keyboard - Use the key just to the left of the 1 key

To make a backtick on the British or International English keyboard - Use the key just to the right of the left shift key

If you have a TURKISH keyboard, and using Turkish - QWERTY PC, in order to type ´, you need press ALT + Ş.

Gizem's comment: In fact for backtick (`) TURKISH keyboard, you should press ALT and comma like this: (ALT,)

I presume you don't have the English keyboard layout. You need to set up the U.S. Input Source, similar to what is described here (actually it's the other way around, you want to Check U.S.): How do I disable the Russian keyboard layout in software?

Then select that Layout and press the key right to left Shift.