N-acetylglucosaminyltransferase I may refer to:

• A-1,3-mannosyl-glycoprotein 2-b-N-acetylglucosaminyltransferase, an enzyme
• Protein N-acetylglucosaminyltransferase, an enzyme

• Four Devas
• Four Dharmadhatu
• Four Dharmadhātu
• Four diamond hotel
• Four-die forging device
• Four dimensiional
• Four dimensionalism
• Four-dimensional topology
• Four Dimensions (Lollipop F album)
• Four Divine Abidings
• Four divisions of society
• Four Doctors
• Four Doctors of Bologna
• Four-document hypothesis
• Four Document Hypothesis (Sunoptic problem)
• Four Document Hypothesis (Synoptic problem)
• Four Dogs Playing Poker (film)
• Four door house
• Four Door Lemon
• Four-dotted Agonopterix Moth
• Fourdrain
• Fourdrinier, Henry
• Fourdrinier machine
• Four (drink)
• Fourdrinoy