diff --git a/README.md b/README.md
index 15766ce3810b67aaa98dd64ac920233c06b0e1ee..cef20a5bc75eb48a494148946e1c6f438e2b86c6 100644
--- a/README.md
+++ b/README.md
@@ -7,3 +7,7 @@ The aim of the project, funded by PNRR-CNS, is to refactor the original, very ol
 The current implementation offers a set of elementary tests to check that the original FORTRAN code can be compiled and executed on a limited set of pre-defined input data. The functionality of this initial stage can be verified by cloning the gitLab repository on a local machine and building the binaries from the `src` folder.
 
 *NOTE:* The building process requires a working installation of the GNU Compiler Collection (`gcc`), of the GNU FORTRAN compiler (`gfortran`) and of the GNU `make` builder.
+
+# License
+
+This project is distributed under the terms of the *GNU General Public License V3.0 or later* (GPL-3.0-or-later). Check the contents of the *COPYING* file for further details.
\ No newline at end of file
diff --git a/build/README.md b/build/README.md
index 2596e698074726fbfbb035f1f95fe7a13d44335a..bd4fe07fd2a7db8b7b645a23a001180531071154 100644
--- a/build/README.md
+++ b/build/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Folder instructions
 
 This directory collects all the output of make builds.
diff --git a/containers/docker/README.md b/containers/docker/README.md
index c6bf1c9e9fc5bfbab6156a968259e6c0f66c386a..555a487d89a97d85acd42a412e535e3ba6e383ff 100644
--- a/containers/docker/README.md
+++ b/containers/docker/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Docker support for the NP-TMcode project
 
 This Dockerfile allows to create mainly:
diff --git a/containers/singularity/README.md b/containers/singularity/README.md
index 04cfdfe1108d63f93ebe707d6f35a5eb1956d580..20e9767c4df0e96126e41ef74e1b3b4b941dda42 100644
--- a/containers/singularity/README.md
+++ b/containers/singularity/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Singularity support for the NP-TMcode project
 
 This `np-tmcode-run.def` file allows to create a np-tmcode-run image, that contains only the pre-built executables, python test scripts, compiled documentation, and the minimal runtime to run them
diff --git a/doc/src/README.md b/doc/src/README.md
index 94056c1801324d3dcb85fffea980b27a26181a20..40ca9e988adb0865d58cb2011fb40b4bda0e3244 100644
--- a/doc/src/README.md
+++ b/doc/src/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Folder instructions
 
 This directory contains the material to build the project documentation with *doxygen*.
diff --git a/src/README.md b/src/README.md
index c345b3895299ffb296e3df970e74dcf92b3aca33..803470ee896cabebd92f61f297f971030136e1d4 100644
--- a/src/README.md
+++ b/src/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Folder instructions
 
 This directory collects the source code of the original programs and the development folders.
diff --git a/src/scripts/README.md b/src/scripts/README.md
index b865eacaa0946125f0a30195fba197fc3f6c385d..59a757141c8c6627065b4b809e774a0bc9f079fd 100644
--- a/src/scripts/README.md
+++ b/src/scripts/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Folder instructions
 
 This directory contains scripts and tools to evaluate the code functionality.
diff --git a/test_data/README.md b/test_data/README.md
index b075b9e1ef924bca544715635cc6537cd8112578..4db4e5af7e9ab05240bbd9a95fb0d6f0efb0a80c 100644
--- a/test_data/README.md
+++ b/test_data/README.md
@@ -1,3 +1,5 @@
+Distributed under the terms of *GNU GPL-3.0-or-later*
+
 # Folder instructions
 
 This directory collects the input files to test the code.