Apple - How to increase font size of Eclipse globally?

Go to Preferences > General > Appearance > Colors and Fonts, expand the "Basic" folder and select "Text Font" and change that to whatever size you like.

For Eclipse Neon: To Increase Ctrl + To reduce Ctrl - for Macs, use the command key, not the control key

Inside the Eclipse.app is a setting for the font size. To make the fonts globally larger edit Eclipse.app » Contents » Eclipse » eclipse.ini and remove the line

-Dorg.eclipse.swt.internal.carbon.smallFonts

from the file. Save the file and restart Eclipse.

Solution for Eclipse Oxygen at MacOS High Sierra (Dec 2017)

1. Open terminal and run commands:

   cd /Applications/Eclipse.app/Contents/Eclipse/plugins/org.eclipse.ui.themes_1.2.1.v20170809-1435/css
   
   vim e4_basestyle.css
   

2. Add a style:

   * {
       font-size: 14;
   }
   

3. Restart Eclipse to apply changes.