GIIS is an abbreviation for:

• Global Indian International School Singapore
• Graduate Institute of Development Studies, absorbed in 2008 into the Graduate Institute of International and Development Studies or Institut de hautes études internationales et du développement, in Geneva, Switzerland

• Peter Prier
• Peter Pringle
• Peter Prior
• Peter Prior (Gulumba)
• Peter Probie
• Peter Problems
• Peter Probst
• Peter Prodromou
• Peter Proksch
• Peter Propping
• Peter Proud
• Peter Proudfoot
• Peter Prusa
• Peter Pruzan
• Peter Pryor
• Peter Przygodda
• Peter P. S. Chen
• Peter Pugh
• Peter Puzzle
• Peter P. Walsh
• Peter Pyszczynski
• Peter Quasdanovich
• Peter Quill (disambiguation)
• Peter Quill (footballer)
• Peter Quilliams