diff --git a/.github/workflows/nix.yml b/.github/workflows/nix.yml
index 8faa7e209a..c0b064cacf 100644
--- a/.github/workflows/nix.yml
+++ b/.github/workflows/nix.yml
@@ -37,6 +37,21 @@ jobs:
       - run: nix build -L .#libpinocchio
       - run: nix build -L .#pinocchio-py
 
+  nix-eigen_5:
+    runs-on: "${{ matrix.os }}-latest"
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu, macos]
+    steps:
+      - uses: actions/checkout@v5
+      - uses: cachix/install-nix-action@v31
+      - uses: cachix/cachix-action@v16
+        with:
+          name: gepetto
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - run: nix build -L .#libpinocchio-eigen_5
+
   check:
     if: always()
     name: check-macos-linux-nix
@@ -44,6 +59,7 @@ jobs:
     needs:
       - nix-full
       - nix-split
+      - nix-eigen_5
 
     runs-on: Ubuntu-latest
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3dd8941bcf..03b23f1f28 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,10 +10,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Changed
 - Homogenize python viewers examples ([#2771](https://github.com/stack-of-tasks/pinocchio/pull/2771))
+
+### Added
 - Add docker images ([#2776](https://github.com/stack-of-tasks/pinocchio/pull/2776))
 - ROS: added jrl_cmakemodules dependency ([#2789](https://github.com/stack-of-tasks/pinocchio/pull/2789))
 
+### Fixed
+- Fix compatibility issues with Eigen5 ([#2779](https://github.com/stack-of-tasks/pinocchio/pull/2779))
+
 ## [3.8.0] - 2025-09-17
 
 ### Added
diff --git a/flake.nix b/flake.nix
index 26ad4f3d23..4f2b7df177 100644
--- a/flake.nix
+++ b/flake.nix
@@ -30,6 +30,16 @@
           };
           packages = {
             default = self'.packages.pinocchio;
+            eigen_5 = pkgs.eigen.overrideAttrs (super: rec {
+              version = "5.0.0";
+              src = pkgs.fetchFromGitLab {
+                inherit (super.src) owner repo;
+                tag = version;
+                hash = "sha256-L1KUFZsaibC/FD6abTXrT3pvaFhbYnw+GaWsxM2gaxM=";
+              };
+              patches = [ ];
+              postPatch = "";
+            });
             pinocchio = pkgs.python3Packages.pinocchio.overrideAttrs (super: {
               propagatedBuildInputs = super.propagatedBuildInputs ++ [ pkgs.example-robot-data ];
               src = pkgs.lib.fileset.toSource {
@@ -71,6 +81,16 @@
                 ];
               };
             });
+
+            libpinocchio-eigen_5 =
+              (self'.packages.libpinocchio.override { eigen = self'.packages.eigen_5; }).overrideAttrs
+                (super: {
+                  pname = "${super.pname}-eigen_5";
+                  cmakeFlags = super.cmakeFlags ++ [
+                    "-DBUILD_WITH_CASADI_SUPPORT=OFF"
+                    "-DBUILD_WITH_COLLISION_SUPPORT=OFF"
+                  ];
+                });
             pinocchio-py = pkgs.python3Packages.pinocchio.overrideAttrs (super: {
               pname = "pinocchio-py";
               cmakeFlags = super.cmakeFlags ++ [ "-DBUILD_STANDALONE_PYTHON_INTERFACE=ON" ];
diff --git a/include/pinocchio/autodiff/casadi.hpp b/include/pinocchio/autodiff/casadi.hpp
index 0340d0121e..8db8c395df 100644
--- a/include/pinocchio/autodiff/casadi.hpp
+++ b/include/pinocchio/autodiff/casadi.hpp
@@ -142,6 +142,18 @@ namespace Eigen
     {
       return std::numeric_limits<double>::digits10;
     }
+
+#if EIGEN_VERSION_AT_LEAST(3, 4, 90)
+    EIGEN_DEVICE_FUNC constexpr static int digits()
+    {
+      return NumTraits<double>::digits();
+    }
+
+    EIGEN_DEVICE_FUNC constexpr static int max_digits10()
+    {
+      return NumTraits<double>::max_digits10();
+    }
+#endif
   };
 } // namespace Eigen
 
@@ -391,7 +403,6 @@ namespace Eigen
       typedef
         typename ScalarBinaryOpTraits<LhsScalar, RhsScalar, scalar_max_op>::ReturnType result_type;
 
-      EIGEN_EMPTY_STRUCT_CTOR(scalar_max_op)
       EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const result_type
       operator()(const LhsScalar & a, const RhsScalar & b) const
       {
@@ -412,7 +423,6 @@ namespace Eigen
       typedef
         typename ScalarBinaryOpTraits<LhsScalar, RhsScalar, scalar_max_op>::ReturnType result_type;
 
-      EIGEN_EMPTY_STRUCT_CTOR(scalar_max_op)
       EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const result_type
       operator()(const LhsScalar & a, const RhsScalar & b) const
       {
@@ -428,14 +438,38 @@ namespace Eigen
       typedef
         typename ScalarBinaryOpTraits<LhsScalar, RhsScalar, scalar_max_op>::ReturnType result_type;
 
-      EIGEN_EMPTY_STRUCT_CTOR(scalar_max_op)
       EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const result_type
       operator()(const LhsScalar & a, const RhsScalar & b) const
       {
         return ::pinocchio::math::internal::call_max<LhsScalar, RhsScalar>::run(a, b);
       }
     };
+
   } // namespace internal
+  namespace numext
+  {
+#if EIGEN_VERSION_AT_LEAST(3, 4, 90)
+    // The function Eigen::internal::gemv_dense_selector::run defined in
+    // Eigen/src/Core/GeneralProduct.h call at some point Eigen::numext::is_exactly_zero function.
+    // Since equality operator is not defined on casadi scalar type this create a compilation error.
+    // To overcome this issue, overload Eigen::numext::equal_strict_impl::run function.
+    template<>
+    struct equal_strict_impl<
+      ::casadi::Matrix<::casadi::SXElem>,
+      ::casadi::Matrix<::casadi::SXElem>,
+      false,
+      true,
+      false,
+      true>
+    {
+      static EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bool
+      run(const ::casadi::Matrix<::casadi::SXElem> &, const ::casadi::Matrix<::casadi::SXElem> &)
+      {
+        return false;
+      }
+    };
+#endif
+  } // namespace numext
 } // namespace Eigen
 
 #include "pinocchio/autodiff/casadi/spatial/se3-tpl.hpp"
diff --git a/include/pinocchio/math/tridiagonal-matrix.hpp b/include/pinocchio/math/tridiagonal-matrix.hpp
index d7005e5e46..10e16b67e9 100644
--- a/include/pinocchio/math/tridiagonal-matrix.hpp
+++ b/include/pinocchio/math/tridiagonal-matrix.hpp
@@ -260,11 +260,11 @@ namespace pinocchio
       subDiagonal().setZero();
     }
 
-    EIGEN_CONSTEXPR Eigen::Index rows() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index rows() const noexcept
     {
       return m_size;
     }
-    EIGEN_CONSTEXPR Eigen::Index cols() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index cols() const noexcept
     {
       return m_size;
     }
@@ -358,11 +358,11 @@ namespace pinocchio
         m_lhs.subDiagonal().asDiagonal() * m_rhs.topRows(reduced_size);
     }
 
-    EIGEN_CONSTEXPR Eigen::Index rows() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index rows() const noexcept
     {
       return m_lhs.rows();
     }
-    EIGEN_CONSTEXPR Eigen::Index cols() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index cols() const noexcept
     {
       return m_rhs.cols();
     }
@@ -407,11 +407,11 @@ namespace pinocchio
         m_lhs.rightCols(reduced_size) * m_rhs.subDiagonal().asDiagonal();
     }
 
-    EIGEN_CONSTEXPR Eigen::Index rows() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index rows() const noexcept
     {
       return m_lhs.rows();
     }
-    EIGEN_CONSTEXPR Eigen::Index cols() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index cols() const noexcept
     {
       return m_rhs.cols();
     }
@@ -496,11 +496,11 @@ namespace pinocchio
       }
     }
 
-    EIGEN_CONSTEXPR Eigen::Index rows() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index rows() const noexcept
     {
       return m_size;
     }
-    EIGEN_CONSTEXPR Eigen::Index cols() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index cols() const noexcept
     {
       return m_size;
     }
@@ -576,11 +576,11 @@ namespace pinocchio
       }
     }
 
-    EIGEN_CONSTEXPR Eigen::Index rows() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index rows() const noexcept
     {
       return m_lhs.rows();
     }
-    EIGEN_CONSTEXPR Eigen::Index cols() const EIGEN_NOEXCEPT
+    EIGEN_CONSTEXPR Eigen::Index cols() const noexcept
     {
       return m_rhs.cols();
     }
diff --git a/include/pinocchio/multibody/joint/joint-revolute.hpp b/include/pinocchio/multibody/joint/joint-revolute.hpp
index bbff93fdbe..9a4b988b40 100644
--- a/include/pinocchio/multibody/joint/joint-revolute.hpp
+++ b/include/pinocchio/multibody/joint/joint-revolute.hpp
@@ -80,9 +80,17 @@ namespace pinocchio
     typedef Matrix3 AngularType;
     typedef Matrix3 AngularRef;
     typedef Matrix3 ConstAngularRef;
+#if EIGEN_VERSION_AT_LEAST(3, 4, 90)
+    typedef typename Vector3::ZeroReturnType LinearType;
+    typedef const typename Vector3::ZeroReturnType ConstLinearType;
+    typedef typename Vector3::ZeroReturnType LinearRef;
+    typedef const typename Vector3::ZeroReturnType ConstLinearRef;
+#else
     typedef typename Vector3::ConstantReturnType LinearType;
+    typedef const typename Vector3::ConstantReturnType ConstLinearType;
     typedef typename Vector3::ConstantReturnType LinearRef;
     typedef const typename Vector3::ConstantReturnType ConstLinearRef;
+#endif
     typedef typename traits<PlainType>::ActionMatrixType ActionMatrixType;
     typedef typename traits<PlainType>::HomogeneousMatrixType HomogeneousMatrixType;
   }; // traits TransformRevoluteTpl
@@ -98,6 +106,7 @@ namespace pinocchio
   {
     EIGEN_MAKE_ALIGNED_OPERATOR_NEW
     PINOCCHIO_SE3_TYPEDEF_TPL(TransformRevoluteTpl);
+    typedef typename traits<TransformRevoluteTpl>::ConstLinearType ConstLinearType;
 
     TransformRevoluteTpl()
     {
@@ -180,9 +189,9 @@ namespace pinocchio
       m_cos = cos;
     }
 
-    LinearType translation() const
+    ConstLinearType translation() const
     {
-      return LinearType::PlainObject::Zero(3);
+      return ConstLinearType::PlainObject::Zero(3);
     }
     AngularType rotation() const
     {
diff --git a/unittest/spatial.cpp b/unittest/spatial.cpp
index 65cb9b9279..828f0920ce 100644
--- a/unittest/spatial.cpp
+++ b/unittest/spatial.cpp
@@ -105,7 +105,7 @@ BOOST_AUTO_TEST_CASE(test_SE3)
   {
     const double prec = Eigen::NumTraits<double>::dummy_precision();
     SE3 M(SE3::Random());
-    M.rotation() += prec * SE3::Matrix3::Random();
+    M.rotation() += 2. * prec * SE3::Matrix3::Random();
     BOOST_CHECK(!M.isNormalized());
 
     SE3 M_normalized = M.normalized();