Will my external hard drive be compatible with MacBooks equipped with USB-C ports?  

Yes, but you will need to purchase an adapter from Apple that will allow you to connect the included USB 3.0 cable to the computer. The adapter can be purchased here: http://www.apple.com/shop/product/MJ1M2AM/A/usb-c-to-usb-adapter.

For MacBooks with only one USB-C port, it is recommended that a multiport adapter be utilized so that the computer can be charged while the hard drive is being used. The multiport adapter can be purchased here: http://www.apple.com/shop/product/MJ1K2AM/A/usb-c-digital-av-multiport-adapter

If an Oyen Digital external drive does not appear to function with a USB to USB-C adapter, it is likely due to insufficient power. In this case, a powered USB-C hub will be required (or an external power supply for MiniPro models).