Planner may refer to:

• A diary for planning
• Planner programming language
• Planner (PIM for Emacs)
• Urban planner
• Route planner
• Meeting and convention planner

Planner (often seen in publications as "PLANNER" although it is not an acronym) is a programming language designed by Carl Hewitt at MIT, and first published in 1969. First, subsets such as Micro-Planner and Pico-Planner were implemented, and then essentially the whole language was implemented as Popler by Julian Davies at the University of Edinburgh in the POP-2 programming language. Derivations such as QA4, Conniver, QLISP and Ether (see Scientific Community Metaphor) were important tools in Artificial Intelligence research in the 1970s, which influenced commercial developments such as KEE and ART.