diff --git a/CMakeLists.txt b/CMakeLists.txt
index dcd0a0bef..7326e7f35 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,8 +3,8 @@ project(openmc C CXX)
 
 # Set version numbers
 set(OPENMC_VERSION_MAJOR 0)
-set(OPENMC_VERSION_MINOR 12)
-set(OPENMC_VERSION_RELEASE 2)
+set(OPENMC_VERSION_MINOR 13)
+set(OPENMC_VERSION_RELEASE 0)
 set(OPENMC_VERSION ${OPENMC_VERSION_MAJOR}.${OPENMC_VERSION_MINOR}.${OPENMC_VERSION_RELEASE})
 configure_file(include/openmc/version.h.in "${CMAKE_BINARY_DIR}/include/openmc/version.h" @ONLY)
 
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 55cfef352..ed790a2e2 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -70,9 +70,9 @@ copyright = '2011-2021, Massachusetts Institute of Technology and OpenMC contrib
 # built documents.
 #
 # The short X.Y version.
-version = "0.12"
+version = "0.13"
 # The full version, including alpha/beta/rc tags.
-release = "0.12.2"
+release = "0.13.0-dev"
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/include/openmc/version.h.in b/include/openmc/version.h.in
index fe282be7c..995f20c3b 100644
--- a/include/openmc/version.h.in
+++ b/include/openmc/version.h.in
@@ -6,7 +6,7 @@ namespace openmc {
 constexpr int VERSION_MAJOR {@OPENMC_VERSION_MAJOR@};
 constexpr int VERSION_MINOR {@OPENMC_VERSION_MINOR@};
 constexpr int VERSION_RELEASE {@OPENMC_VERSION_RELEASE@};
-constexpr bool VERSION_DEV {false};
+constexpr bool VERSION_DEV {true};
 constexpr std::array<int, 3> VERSION {VERSION_MAJOR, VERSION_MINOR, VERSION_RELEASE};
 
 }
diff --git a/openmc/__init__.py b/openmc/__init__.py
index bd27ab308..50246cdd8 100644
--- a/openmc/__init__.py
+++ b/openmc/__init__.py
@@ -34,4 +34,4 @@ from . import examples
 # Import a few convencience functions that used to be here
 from openmc.model import rectangular_prism, hexagonal_prism
 
-__version__ = '0.12.2'
+__version__ = '0.13.0-dev'