gretl is an open-source statistical package, mainly for econometrics. The name is an acronym for Gnu Regression, Econometrics and Time-series Library.It has a graphical user interface (GUI) and can be used together with TRAMO/SEATS, R, Stata, Python, Octave, and Ox. It is written in C, uses GTK+ as widget toolkit for creating its GUI, and uses gnuplot for generating graphs.