diff --git a/.gitignore b/.gitignore
index dd8dfb14a96..32ef7919ab4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,6 +25,7 @@ examples/**/*.xml
 
 # Documentation builds
 docs/build
+docs/doxygen/xml
 docs/source/_images/*.pdf
 docs/source/_images/*.aux
 docs/source/pythonapi/generated/
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 61301bdb499..7594ed5f2b6 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -7,6 +7,8 @@ build:
   jobs:
     post_checkout:
       - git fetch --unshallow || true
+      - cd docs/doxygen && doxygen && cd -
+
 sphinx:
   configuration: docs/source/conf.py
 
diff --git a/docs/Makefile b/docs/Makefile
index a93338df31f..e320432a20b 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -45,6 +45,7 @@ help:
 clean:
 	-rm -rf $(BUILDDIR)/*
 	-rm -rf source/pythonapi/generated/
+	-rm -rf doxygen/xml
 
 html:
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
diff --git a/docs/doxygen/Doxyfile b/docs/doxygen/Doxyfile
new file mode 100644
index 00000000000..186fd8a011e
--- /dev/null
+++ b/docs/doxygen/Doxyfile
@@ -0,0 +1,14 @@
+# Doxyfile 1.9.1
+
+# This file describes the settings to be used by the documentation system
+# doxygen (www.doxygen.org) for a project.
+
+# Difference with default Doxyfile 1.9.1
+PROJECT_NAME           = OpenMC
+QUIET                  = YES
+WARN_IF_UNDOCUMENTED   = NO
+INPUT                  = ../../include/openmc/
+RECURSIVE              = YES
+GENERATE_HTML          = NO
+GENERATE_LATEX         = NO
+GENERATE_XML           = YES
diff --git a/docs/source/capi/index.rst b/docs/source/capi/index.rst
index 1777e795ad7..e924aa6e2a9 100644
--- a/docs/source/capi/index.rst
+++ b/docs/source/capi/index.rst
@@ -46,43 +46,20 @@ Type Definitions
 Functions
 ---------
 
-.. c:function:: int openmc_calculate_volumes()
+..
+   Once documentation is complete in capi.h, use:
+   .. doxygenfile:: capi.h
+   to populate this documentation without using
+   .. doxygenfunction::
+   for every function.
 
-   Run a stochastic volume calculation
+.. doxygenfunction:: openmc_calculate_volumes
 
-   :return: Return status (negative if an error occurred)
-   :rtype: int
-
-.. c:function:: int openmc_cell_get_fill(int32_t index, int* type, int32_t** indices, int32_t* n)
-
-   Get the fill for a cell
-
-   :param int32_t index: Index in the cells array
-   :param int* type: Type of the fill
-   :param int32_t** indices: Array of material indices for cell
-   :param int32_t* n: Length of indices array
-   :return: Return status (negative if an error occurred)
-   :rtype: int
-
-.. c:function:: int openmc_cell_get_id(int32_t index, int32_t* id)
+.. doxygenfunction:: openmc_cell_get_fill
 
-   Get the ID of a cell
+.. doxygenfunction:: openmc_cell_get_id
 
-   :param int32_t index: Index in the cells array
-   :param int32_t* id: ID of the cell
-   :return: Return status (negative if an error occurred)
-   :rtype: int
-
-.. c:function:: int openmc_cell_get_temperature(int32_t index, const int32_t* instance, double* T)
-
-   Get the temperature of a cell
-
-   :param int32_t index: Index in the cells array
-   :param int32_t* instance: Which instance of the cell. If a null pointer is passed, the temperature
-                             of the first instance is returned.
-   :param double* T: temperature of the cell
-   :return: Return status (negative if an error occurred)
-   :rtype: int
+.. doxygenfunction:: openmc_cell_get_temperature
 
 .. c:function:: int openmc_cell_get_density(int32_t index, const int32_t* instance, double* density)
 
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 3a2e7fb93b1..699b75d340e 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -11,7 +11,7 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-import sys, os
+import sys, os, subprocess
 
 # Determine if we're on Read the Docs server
 on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
@@ -37,6 +37,7 @@
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
+    'breathe',
     'sphinx.ext.autodoc',
     'sphinx.ext.napoleon',
     'sphinx.ext.autosummary',
@@ -47,6 +48,7 @@
 ]
 if not on_rtd:
     extensions.append('sphinxcontrib.rsvgconverter')
+    subprocess.run(['doxygen'], cwd='../doxygen')
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
@@ -117,6 +119,10 @@
 # A list of ignored prefixes for module index sorting.
 #modindex_common_prefix = []
 
+# -- Options breathe + doxygen -------------------------------------------------
+
+breathe_projects = {"OpenMC": "../doxygen/xml"}
+breathe_default_project = "OpenMC"
 
 # -- Options for HTML output ---------------------------------------------------
 
diff --git a/include/openmc/capi.h b/include/openmc/capi.h
index 911654d318f..f8b13ae5826 100644
--- a/include/openmc/capi.h
+++ b/include/openmc/capi.h
@@ -9,14 +9,41 @@
 extern "C" {
 #endif
 
+//! Run a stochastic volume calculation
+//
+//! \return Status (negative if an error occurred)
 int openmc_calculate_volumes();
+
 int openmc_cell_filter_get_bins(
   int32_t index, const int32_t** cells, int32_t* n);
+
+//! Get the fill for a cell
+//
+//! \param index Index in the cells array
+//! \param type Type of the fill
+//! \param indices Array of material indices for cell
+//! \param n Length of indices array
+//! \return Status (negative if an error occurred)
 int openmc_cell_get_fill(
   int32_t index, int* type, int32_t** indices, int32_t* n);
+
+//! Get the ID of a cell
+//
+//! \param index Index in the cells array
+//! \param id ID of the cell
+//! \return Status (negative if an error occurred)
 int openmc_cell_get_id(int32_t index, int32_t* id);
+
+//! Get the temperature of a cell
+//
+//! \param index Index in the cells array
+//! \param instance Which instance of the cell. If a null pointer is
+//!                 passed, the temperature of the first instance is returned.
+//! \param T temperature of the cell
+//!\return Status (negative if an error occurred)
 int openmc_cell_get_temperature(
   int32_t index, const int32_t* instance, double* T);
+
 int openmc_cell_get_density(
   int32_t index, const int32_t* instance, double* rho);
 int openmc_cell_get_translation(int32_t index, double xyz[]);
diff --git a/pyproject.toml b/pyproject.toml
index 098487c06ed..c769fb7d760 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -40,6 +40,7 @@ dependencies = [
 [project.optional-dependencies]
 depletion-mpi = ["mpi4py"]
 docs = [
+    "breathe",
     "sphinx",
     "sphinxcontrib-katex",
     "sphinx-numfig",