diff --git a/pkgs/development/libraries/physics/fastnlo_toolkit/default.nix b/pkgs/development/libraries/physics/fastnlo-toolkit/default.nix
similarity index 98%
rename from pkgs/development/libraries/physics/fastnlo_toolkit/default.nix
rename to pkgs/development/libraries/physics/fastnlo-toolkit/default.nix
index 049cfcb04d5a..66a3bf5128f5 100644
--- a/pkgs/development/libraries/physics/fastnlo_toolkit/default.nix
+++ b/pkgs/development/libraries/physics/fastnlo-toolkit/default.nix
@@ -14,7 +14,7 @@
 }:
 
 stdenv.mkDerivation rec {
-  pname = "fastnlo_toolkit";
+  pname = "fastnlo-toolkit";
   version = "2.5.0-2826";
 
   src = fetchurl {
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 9d4939c34cbf..13aedede18f0 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -264,7 +264,8 @@ mapAliases ({
   ### F ###
 
   faustStk = faustPhysicalModeling; # Added 2023-05-16
-  fastnlo = fastnlo_toolkit; # Added 2021-04-24
+  fastnlo = fastnlo-toolkit; # Added 2021-04-24
+  fastnlo_toolkit = fastnlo-toolkit; # Added 2024-01-03
   inherit (luaPackages) fennel; # Added 2022-09-24
   fetchFromGithub = throw "You meant fetchFromGitHub, with a capital H"; # preserve
   findimagedupes = throw "findimagedupes has been removed because the perl bindings are no longer compatible"; # Added 2023-07-10
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 2df02fe4415b..33e87aa81623 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -39992,7 +39992,7 @@ with pkgs;
 
   fastjet-contrib = callPackage ../development/libraries/physics/fastjet-contrib { };
 
-  fastnlo_toolkit = callPackage ../development/libraries/physics/fastnlo_toolkit { };
+  fastnlo-toolkit = callPackage ../development/libraries/physics/fastnlo-toolkit { };
 
   geant4 = libsForQt5.callPackage ../development/libraries/physics/geant4 { };
 
diff --git a/pkgs/top-level/python-aliases.nix b/pkgs/top-level/python-aliases.nix
index 3274c0638dfa..c03982192c98 100644
--- a/pkgs/top-level/python-aliases.nix
+++ b/pkgs/top-level/python-aliases.nix
@@ -145,6 +145,7 @@ mapAliases ({
   face_recognition_models = face-recognition-models; # added 2022-10-15
   factory_boy = factory-boy; # added 2023-10-08
   fake_factory = throw "fake_factory has been removed because it is unused and deprecated by upstream since 2016."; # added 2022-05-30
+  fastnlo_toolkit = fastnlo-toolkit; # added 2024-01-03
   faulthandler = throw "faulthandler is built into ${python.executable}"; # added 2021-07-12
   inherit (super.pkgs) fetchPypi; # added 2023-05-25
   filebrowser_safe = filebrowser-safe; # added 2024-01-03
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index ad5394fb13fd..9cb85e6ad622 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -3923,7 +3923,7 @@ self: super: with self; {
 
   fastjsonschema = callPackage ../development/python-modules/fastjsonschema { };
 
-  fastnlo_toolkit = toPythonModule (pkgs.fastnlo_toolkit.override {
+  fastnlo-toolkit = toPythonModule (pkgs.fastnlo-toolkit.override {
     withPython = true;
     inherit (self) python;
   });