diff --git a/docs/api/utilities.rst b/docs/api/utilities.rst
index af02d43fc..d4c68d641 100644
--- a/docs/api/utilities.rst
+++ b/docs/api/utilities.rst
@@ -65,28 +65,6 @@ Non-negative least squares
 .. autofunction:: nnls
 
 
-Second Order Optimization
--------------------------
-
-.. currentmodule:: optax.second_order
-
-.. autosummary::
-    fisher_diag
-    hessian_diag
-    hvp
-
-Fisher diagonal
-~~~~~~~~~~~~~~~
-.. autofunction:: fisher_diag
-
-Hessian diagonal
-~~~~~~~~~~~~~~~~
-.. autofunction:: hessian_diag
-
-Hessian vector product
-~~~~~~~~~~~~~~~~~~~~~~
-.. autofunction:: hvp
-
 
 Tree
 ----
diff --git a/optax/CHANGELOG.md b/optax/CHANGELOG.md
index bc2477718..b8392d2c6 100644
--- a/optax/CHANGELOG.md
+++ b/optax/CHANGELOG.md
@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Removed
+
+- Removed deprecated `optax.second_order.hvp`, `optax.second_order.hessian_diag`,
+  and `optax.second_order.fisher_diag`. These were deprecated in 0.2.7 and
+  scheduled for removal in 0.2.9.
+
 ## [0.2.8] - 2026-03-20
 
 ### Changed
diff --git a/optax/second_order/__init__.py b/optax/second_order/__init__.py
index a2cebadd1..a17a6dce6 100644
--- a/optax/second_order/__init__.py
+++ b/optax/second_order/__init__.py
@@ -13,9 +13,3 @@
 # limitations under the License.
 # ==============================================================================
 """The second order optimization sub-package."""
-
-# pylint: disable=g-importing-member
-
-from optax.second_order._deprecated import fisher_diag
-from optax.second_order._deprecated import hessian_diag
-from optax.second_order._deprecated import hvp
diff --git a/optax/second_order/_deprecated.py b/optax/second_order/_deprecated.py
deleted file mode 100644
index 9875c153f..000000000
--- a/optax/second_order/_deprecated.py
+++ /dev/null
@@ -1,120 +0,0 @@
-# Copyright 2019 DeepMind Technologies Limited. All Rights Reserved.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-# ==============================================================================
-"""Deprecated second order utilities kept for backward compatibility.
-"""
-
-import abc
-import functools
-from typing import Any, Protocol
-
-import jax
-from jax import flatten_util
-import jax.numpy as jnp
-from optax._src.deprecations import warn_deprecated_function  # pylint: disable=g-importing-member
-
-
-def _ravel(p: Any) -> jax.Array:
-  return flatten_util.ravel_pytree(p)[0]
-
-
-class LossFn(Protocol):
-  """A loss function to be optimized."""
-
-  @abc.abstractmethod
-  def __call__(
-      self, params: Any, inputs: jax.Array, targets: jax.Array
-  ) -> jax.Array:
-    ...
-
-
-@functools.partial(warn_deprecated_function, version_removed='0.2.9')
-def hvp(
-    loss: LossFn,
-    v: jax.Array,
-    params: Any,
-    inputs: jax.Array,
-    targets: jax.Array,
-) -> jax.Array:
-  """Performs an efficient vector-Hessian (of `loss`) product.
-
-  .. deprecated: 0.2.7. This function will be removed in 0.2.9
-
-  Args:
-    loss: the loss function.
-    v: a vector of size `ravel(params)`.
-    params: model parameters.
-    inputs: inputs at which `loss` is evaluated.
-    targets: targets at which `loss` is evaluated.
-
-  Returns:
-    An Array corresponding to the product of `v` and the Hessian of `loss`
-    evaluated at `(params, inputs, targets)`.
-  """
-  _, unravel_fn = flatten_util.ravel_pytree(params)
-  loss_fn = lambda p: loss(p, inputs, targets)
-  return jax.jvp(jax.grad(loss_fn), [params], [unravel_fn(v)])[1]
-
-
-@functools.partial(warn_deprecated_function, version_removed='0.2.9')
-def hessian_diag(
-    loss: LossFn,
-    params: Any,
-    inputs: jax.Array,
-    targets: jax.Array,
-) -> jax.Array:
-  """Computes the diagonal hessian of `loss` at (`inputs`, `targets`).
-
-  .. deprecated: 0.2.7. This function will be removed in 0.2.9
-
-  Args:
-    loss: the loss function.
-    params: model parameters.
-    inputs: inputs at which `loss` is evaluated.
-    targets: targets at which `loss` is evaluated.
-
-  Returns:
-    A DeviceArray corresponding to the product to the Hessian of `loss`
-    evaluated at `(params, inputs, targets)`.
-  """
-  vs = jnp.eye(_ravel(params).size)
-  comp = lambda v: jnp.vdot(v, _ravel(hvp(loss, v, params, inputs, targets)))
-  return jax.vmap(comp)(vs)
-
-
-@functools.partial(warn_deprecated_function, version_removed='0.2.9')
-def fisher_diag(
-    negative_log_likelihood: LossFn,
-    params: Any,
-    inputs: jax.Array,
-    targets: jax.Array,
-) -> jax.Array:
-  """Computes the diagonal of the (observed) Fisher information matrix.
-
-  .. deprecated: 0.2.7. This function will be removed in 0.2.9
-
-  Args:
-    negative_log_likelihood: the negative log likelihood function with expected
-      signature `loss = fn(params, inputs, targets)`.
-    params: model parameters.
-    inputs: inputs at which `negative_log_likelihood` is evaluated.
-    targets: targets at which `negative_log_likelihood` is evaluated.
-
-  Returns:
-    An Array corresponding to the product to the Hessian of
-    `negative_log_likelihood` evaluated at `(params, inputs, targets)`.
-  """
-  return jnp.square(
-      _ravel(jax.grad(negative_log_likelihood)(params, inputs, targets))
-  )