diff --git a/.github/workflows/check.yaml b/.github/workflows/check.yaml
index 41afacbd..c461bca6 100644
--- a/.github/workflows/check.yaml
+++ b/.github/workflows/check.yaml
@@ -21,10 +21,10 @@ jobs:
           python-version: "3.11"  # minimum supported lang version
 
       - name: Install dependencies
-        run: python -m pip install tox
+        run: python -m pip install hatch
 
       - name: Run
-        run: tox -e linter
+        run: hatch run lint:check
 
   mypy:
     name: mypy
@@ -42,10 +42,10 @@ jobs:
           python-version: "3.11"  # minimum supported lang version
 
       - name: Install dependencies
-        run: python -m pip install tox
+        run: python -m pip install hatch
 
       - name: Check MyPy
-        run: tox -e mypy
+        run: hatch run mypy:check
 
   pkglint:
     name: pkglint
@@ -63,10 +63,10 @@ jobs:
           python-version: "3.11"  # minimum supported lang version
 
       - name: Install dependencies
-        run: python -m pip install tox
+        run: python -m pip install hatch
 
       - name: Run
-        run: tox -e pkglint
+        run: hatch run pkglint:check
 
   markdownlint:
     # https://github.com/marketplace/actions/markdown-lint
@@ -100,10 +100,10 @@ jobs:
           python-version: "3.11"  # minimum supported lang version
 
       - name: Install dependencies
-        run: python -m pip install tox
+        run: python -m pip install hatch
 
       - name: Run
-        run: tox -e docs
+        run: hatch run docs:build
 
   super-linter:
     name: super-linter
diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 069fc8c2..2d87c299 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -47,14 +47,10 @@ jobs:
         run: unshare -rn echo "unshare works"
 
       - name: Install dependencies
-        run: python -m pip install tox
+        run: python -m pip install hatch
 
       - name: Run tests
-        run: tox -e py
-
-      - name: Run tests for pyo3_test
-        working-directory: ./e2e/pyo3_test/
-        run: tox -e py
+        run: hatch run test:test
 
       - name: Upload coverage
         uses: actions/upload-artifact@v4
@@ -143,7 +139,7 @@ jobs:
         run: unshare -rn echo "unshare works"
 
       - name: Install dependencies
-        run: python -m pip install tox
+        run: python -m pip install hatch
 
       - name: Run tests
         run: ./e2e/test_${{ matrix.test-script }}.sh
@@ -183,12 +179,9 @@ jobs:
           cache: pip
           cache-dependency-path: |
             **/pyproject.toml
-            **/tox.ini
 
       - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip
-          python -m pip install coverage[toml]
+        run: python -m pip install hatch
 
       - name: Download coverage data
         uses: actions/download-artifact@v4
@@ -198,10 +191,10 @@ jobs:
 
       - name: Coverage report
         run: |
-          coverage combine
-          coverage html
-          coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
-          coverage report --fail-under=60
+          hatch run coverage-report:coverage combine
+          hatch run coverage-report:coverage html
+          hatch run coverage-report:coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
+          hatch run coverage-report:coverage report --fail-under=60
 
       - name: Upload report
         uses: actions/upload-artifact@v4
diff --git a/.gitignore b/.gitignore
index 4b36b777..36a502ff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,7 +13,8 @@ __pycache__/
 /artifacts
 /build-logs/
 /.pypirc
-/.tox/
+.pytest_cache/
+/.hatch/
 /node_modules/
 /package-lock.json
 /package.json
@@ -29,3 +30,5 @@ __pycache__/
 /overrides/
 /docs/_build/
 /docs/example/bootstrap-output
+
+/.mypy_cache/
diff --git a/.mergify.yml b/.mergify.yml
index 303c6254..f06bd6b5 100644
--- a/.mergify.yml
+++ b/.mergify.yml
@@ -2,10 +2,10 @@ pull_request_rules:
   - name: Add CI label
     conditions:
       - or:
-          - "title~=^tox:"
+          - "title~=^hatch:"
           - "title~=^ci:"
           - "title~=^e2e:"
-          - files~=tox.ini
+          - files~=pyproject.toml
           - files~=.github/
           - files~=.markdownlint-config.yaml
           - files~=tests/
diff --git a/docs/develop.md b/docs/develop.md
index caff9d27..e60d038c 100644
--- a/docs/develop.md
+++ b/docs/develop.md
@@ -2,12 +2,13 @@
 
 ## Unit tests and linter
 
-The unit tests and linter rely on [tox](https://tox.wiki/) and a
-recent version of Python 3 (at least 3.9).
+The unit tests and linter now use [Hatch](https://hatch.pypa.io/) and a
+recent version of Python (as defined in `pyproject.toml` under `project.requires-python`).
 
-Run `tox` with no arguments to run all of the tests. Use one of the
-specific target environments for running fewer or different
-tests. Refer to `tox.ini` for the list of possible targets.
+To run all default checks and tests (linters, unit tests, etc.), you can typically run `hatch run`.
+To execute specific environments or scripts defined in `pyproject.toml`, use the command `hatch run <env_name>:<script_name>`.
+For instance, linters might be run with `hatch run lint:check`, and unit tests with `hatch run test:test`.
+Consult the `[tool.hatch.envs]` and `[tool.hatch.matrix]` sections in `pyproject.toml` for a comprehensive list of available environments, scripts, and their configurations.
 
 ## End-to-end tests
 
@@ -28,3 +29,5 @@ writing to INFO level to show what is starting and stopping, respectively.
 
 Detailed messages should be logged to DEBUG level so they will not appear on the
 console by default.
+
+### Building documentation
diff --git a/e2e/common.sh b/e2e/common.sh
index 3f397811..a504c9a3 100644
--- a/e2e/common.sh
+++ b/e2e/common.sh
@@ -25,8 +25,12 @@ mkdir -p "$OUTDIR/build-logs"
 
 # Recreate the virtualenv with fromager installed
 # command_pre hook creates cov.pth
-tox -e e2e -r
-source .tox/e2e/bin/activate
+# tox -e e2e -r
+# source .tox/e2e/bin/activate
+hatch env remove e2e || true # Remove the e2e env if it exists, ignore error if it doesn't
+hatch env create e2e # Ensures the environment exists and dependencies are installed
+hatch run e2e:setup-cov # Run the coverage setup script
+source "$(hatch env find e2e)/bin/activate"
 
 # Set a variable to constrain packages used in the tests
 export FROMAGER_CONSTRAINTS_FILE="${SCRIPTDIR}/constraints.txt"
diff --git a/e2e/pyo3_test/MANIFEST.in b/e2e/pyo3_test/MANIFEST.in
index a4efd322..c708d016 100644
--- a/e2e/pyo3_test/MANIFEST.in
+++ b/e2e/pyo3_test/MANIFEST.in
@@ -1,4 +1,6 @@
 graft python
 graft rust
-include Cargo.toml Cargo.lock tests.py tox.ini
+include Cargo.toml Cargo.lock tests.py
 exclude .cargo vendor
+graft src
+global-exclude *.py[cod]
diff --git a/e2e/setup_coverage.py b/e2e/setup_coverage.py
new file mode 100644
index 00000000..c3b16730
--- /dev/null
+++ b/e2e/setup_coverage.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+"""Simple coverage setup for E2E tests."""
+
+import pathlib
+import sys
+import site
+
+def setup_coverage():
+    """Create coverage.pth file for subprocess coverage collection."""
+    # Get the virtual environment root
+    venv_root = pathlib.Path(sys.prefix)
+    
+    # Find site-packages directory
+    site_packages_dirs = [pathlib.Path(p) for p in site.getsitepackages()]
+    
+    # Find the one that's in our virtual environment
+    site_packages = None
+    for sp in site_packages_dirs:
+        if str(sp).startswith(str(venv_root)):
+            site_packages = sp
+            break
+    
+    if not site_packages:
+        site_packages = site_packages_dirs[0]  # fallback
+    
+    # Create coverage.pth file
+    cov_pth = site_packages / "cov.pth"
+    cov_pth.parent.mkdir(parents=True, exist_ok=True)
+    cov_pth.write_text("import coverage; coverage.process_startup()")
+    
+    print(f"Coverage setup complete: {cov_pth}")
+
+if __name__ == "__main__":
+    setup_coverage() 
diff --git a/pyproject.toml b/pyproject.toml
index 5f372837..556954e9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -109,7 +109,7 @@ relative_files = true
 source = ["fromager", "tests/"]
 
 [tool.coverage.paths]
-source = ["src/fromager", ".tox/**/site-packages/fromager"]
+source = ["src/fromager", ".hatch/**/site-packages/fromager"]
 tests = ["tests/"]
 
 [tool.coverage.report]
@@ -194,3 +194,92 @@ reportUnusedParameter = false
 reportAny = false
 reportImplicitOverride = false
 reportAttributeAccessIssue = false  # adding our own private property on click commands
+
+[tool.hatch.envs.default]
+# No specific python version here, so it uses the active Python by default.
+dependencies = []
+
+[tool.hatch.envs.test]
+# Corresponds to the default test environment
+dependencies = [
+  "coverage[toml]!=4.4,>=4.0",
+  "pytest",
+  "requests-mock",
+  "twine>=6.1.0",
+  "hatchling",
+  "hatch-vcs",
+]
+# {args:tests} allows passing arguments to specify which tests to run
+scripts.test = "python -m coverage run -m pytest --log-level DEBUG -vv {args:tests}"
+
+[tool.hatch.envs.coverage-report]
+description = "Report coverage over all test runs."
+# Depends on test environment to have run and generated coverage data
+depends-on = ["test"] # Add "e2e" if its coverage data should be combined.
+dependencies = ["coverage[toml]"]
+skip-install = true
+detached = true # Allows running in parallel
+scripts.report = [
+  "coverage combine",
+  "coverage report",
+]
+
+[tool.hatch.envs.lint]
+description = "Run linters."
+dependencies = [
+  "ruff",
+  "packaging",
+  "PyYAML",
+]
+scripts.check = [
+  "ruff check src tests",
+  "ruff format --check src tests",
+  "python ./e2e/mergify_lint.py",
+]
+skip-install = true # Corresponds to skipping project installation for linting
+
+[tool.hatch.envs.fix]
+description = "Apply auto-fixes."
+dependencies = ["ruff"]
+scripts.fix = [
+  "ruff format src tests docs",
+  "ruff check --fix src tests docs",
+]
+skip-install = true
+
+[tool.hatch.envs.e2e]
+description = "Run end-to-end tests."
+dependencies = ["coverage[toml]", "twine"]
+env-vars.COVERAGE_PROCESS_START = "{root}/pyproject.toml"
+# Script to create cov.pth for coverage in subprocesses
+scripts.setup-cov = "python e2e/setup_coverage.py"
+# Generic script to run any command in the e2e environment
+# e.g. hatch run e2e:run ./e2e/test_bootstrap.sh
+scripts.run = "{args}"
+
+[tool.hatch.envs.mypy]
+description = "Python type checking with mypy."
+features = ["mypy"]
+scripts.check = [
+  "mypy -p fromager",
+  "mypy tests/",
+]
+
+[tool.hatch.envs.pkglint]
+description = "Check package and distribution."
+features = ["build"]
+dependencies = ["check-python-versions"]
+scripts.check = [
+  "python -m build",
+  "twine check dist/*.tar.gz dist/*.whl",
+  "check-python-versions --only pyproject.toml,.github/workflows/test.yml",
+]
+
+[tool.hatch.envs.docs]
+description = "Sphinx docs."
+features = ["docs"]
+scripts.build = "sphinx-build -M html docs docs/_build -j auto --keep-going {args:--fail-on-warning --fresh-env -n}"
+
+# Default environments to run if `hatch run` is called without arguments
+[tool.hatch.matrix]
+default.envs = ["test", "lint", "mypy", "docs", "coverage-report"]
diff --git a/tox.ini b/tox.ini
deleted file mode 100644
index 7186e876..00000000
--- a/tox.ini
+++ /dev/null
@@ -1,88 +0,0 @@
-[tox]
-minversion = 3.2.0
-envlist=py,linter,mypy,docs,coverage-report
-
-[testenv]
-extras = test
-deps =
-    hatchling
-commands =
-    python -m coverage run -m pytest \
-      --log-level DEBUG \
-      -vv \
-      {posargs:tests}
-
-[testenv:coverage-report]
-description = Report coverage over all test runs.
-basepython = py312
-depends = py,py3{11,12},e2e
-deps = coverage[toml]
-skip_install = true
-parallel_show_output = true
-commands =
-    coverage combine
-    coverage report
-
-[testenv:linter]
-base_python=python3.11
-deps=
-    ruff
-    packaging
-    PyYAML
-commands =
-    ruff check src tests
-    ruff format --check src tests
-    python ./e2e/mergify_lint.py
-skip_install = true
-skip_sdist = true
-
-[testenv:fix]
-base_python=python3.11
-deps=
-    ruff
-commands =
-    ruff format src tests docs
-    ruff check --fix src tests docs
-skip_install = true
-skip_sdist = true
-
-[testenv:cli]
-base_python=python3.11
-deps = .
-commands =
-    fromager {posargs}
-
-[testenv:e2e]
-set_env =
-    COVERAGE_PROCESS_START={toxinidir}/pyproject.toml
-commands_pre =
-    {envpython} -c 'import pathlib; pathlib.Path("{env_site_packages_dir}/cov.pth").write_text("import coverage; coverage.process_startup()")'
-deps =
-    .
-    coverage[toml]
-# empty commands
-commands =
-
-[testenv:mypy]
-description = Python type checking with mypy
-extras = mypy
-commands =
-  mypy -p fromager
-  mypy tests/
-
-[testenv:pkglint]
-base_python=python3.11
-deps=
-    .[build]
-    check-python-versions
-commands=
-    python -m build
-    twine check dist/*.tar.gz dist/*.whl
-    check-python-versions --only pyproject.toml,.github/workflows/test.yml
-
-[testenv:docs]
-description = sphinx docs
-basepython = python3.11
-deps = .[docs]
-commands =
-    sphinx-build -M html docs docs/_build -j auto --keep-going {posargs:--fail-on-warning --fresh-env -n}