NIB, nib or NiB may refer to:

• Nib (pen), a part of a quill, dip pen or fountain pen
• Nib, partially processed cocoa bean
• Twizzlers Nibs, a bite-size cherry-flavored licorice candy
• Nibs or his nibs, a term used in the card game cribbage
• Nibs, one of the lost boys in the book Peter Pan
• "New in Box"
• NIB or news-in-brief, a term used in journalism to denote a short news summary or a newsflash
• Neodymium magnet or NIB, a powerful magnet made from neodymium, iron, and boron
• N.I.B., a song by Black Sabbath
• Nib, a type of variable in PBASIC which stores Nibble values in the range of 0 to 15
• Nib, the generic name assigned to .nib and .xib files, short for NeXT Interface Builder, the default file format for Apple's Interface Builder.
• Net Insurance Benefits, net cash flows from a life settlement portfolio
• NiB, Nickel Boron plating, a form of Electroless nickel coating

In companies and organizations:

• National Institute of Building Sciences, a non-profit private organization
• National Irish Bank, a major bank in Ireland
• National Intercollegiate Band, an American band sponsored by Kappa Kappa Psi and Tau Beta Sigma, honorary band fraternity and sorority
• Nordic Investment Bank, the joint international financial institution of Denmark, Finland, Iceland, Norway, and Sweden
• Novin Investment Bank, first private investment bank in Iran
• nib Health Funds, an Australian private health insurer
• Amtrak station code NIB for New Iberia (Amtrak station), in Louisiana United States
• National Internet Backbone, the internet backbone of Bharat Sanchar Nigam Limited (BSNL)

Interface Builder is a software development application for Apple's Mac OS X operating system. It is part of Xcode (formerly Project Builder), the Apple Developer Connection developer's toolset. Interface Builder allows Cocoa and Carbon developers to create interfaces for applications using a graphical user interface. The resulting interface is stored as a .nib file, short for NeXT Interface Builder, or more recently, as a .xib file.