Vadamarachchi (Tamil: வடமராட்சி Vaṭamarāṭci, Sinhala: වඩමාරච්චි) is one of the three historic regions of the Jaffna peninsula in northern Sri Lanka. The other two regions are Thenmarachchi and Valikamam. Alternative spellings include Vadamarachi, Vadamaraachi or Vadamaraadchi.

Vadamarachchi translates to "possession of northerners" or "rule of the northerners" in English. It is derived from the Tamil words vadamar (northerners) and achchi (possession or rule).

• Thenmarachchi
• Valikamam