diff --git a/INSTALL.rst.txt b/INSTALL.rst.txt
index 130306d06c07..f136b7cfcd32 100644
--- a/INSTALL.rst.txt
+++ b/INSTALL.rst.txt
@@ -75,7 +75,8 @@ skipped when running the test suite if no Fortran compiler is available.  For
 building Scipy a Fortran compiler is needed though, so we include some details
 on Fortran compilers in the rest of this section.
 
-On OS X and Linux, all common compilers will work.
+On OS X and Linux, all common compilers will work. The minimum supported GCC
+version is 6.5.
 
 For Fortran, ``gfortran`` works, ``g77`` does not.  In case ``g77`` is
 installed then ``g77`` will be detected and used first.  To explicitly select
diff --git a/doc/source/user/building.rst b/doc/source/user/building.rst
index 4bd0b7183ea0..81f6d33a797b 100644
--- a/doc/source/user/building.rst
+++ b/doc/source/user/building.rst
@@ -59,7 +59,7 @@ Building NumPy requires the following software installed:
    MSVC and Clang compilers. Compilers from other vendors such as Intel,
    Absoft, Sun, NAG, Compaq, Vast, Portland, Lahey, HP, IBM are only
    supported in the form of community feedback, and may not work out of the
-   box.  GCC 4.x (and later) compilers are recommended. On ARM64 (aarch64)
+   box.  GCC 6.5 (and later) compilers are recommended. On ARM64 (aarch64)
    GCC 8.x (and later) are recommended.
 
 3) Linear Algebra libraries