diff --git a/CMakeLists.txt b/CMakeLists.txt
index ca81fad1..f6850e84 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -198,6 +198,7 @@ set (LOOT_API_HEADERS "${CMAKE_SOURCE_DIR}/include/loot/api.h"
                       "${CMAKE_SOURCE_DIR}/include/loot/exception/cyclic_interaction_error.h"
                       "${CMAKE_SOURCE_DIR}/include/loot/exception/file_access_error.h"
                       "${CMAKE_SOURCE_DIR}/include/loot/exception/git_state_error.h"
+                      "${CMAKE_SOURCE_DIR}/include/loot/exception/undefined_group_error.h"
                       "${CMAKE_SOURCE_DIR}/include/loot/enum/game_type.h"
                       "${CMAKE_SOURCE_DIR}/include/loot/enum/log_level.h"
                       "${CMAKE_SOURCE_DIR}/include/loot/enum/message_type.h"
diff --git a/docs/api/reference.rst b/docs/api/reference.rst
index 8f4cdff6..3a5ccb4d 100644
--- a/docs/api/reference.rst
+++ b/docs/api/reference.rst
@@ -96,6 +96,9 @@ Exceptions
 .. doxygenclass:: loot::FileAccessError
    :members:
 
+.. doxygenclass:: loot::UndefinedGroupError
+   :members:
+
 Error Categories
 ================
 
diff --git a/include/loot/api.h b/include/loot/api.h
index b8990c27..f017be27 100644
--- a/include/loot/api.h
+++ b/include/loot/api.h
@@ -37,6 +37,7 @@
 #include "loot/exception/error_categories.h"
 #include "loot/exception/file_access_error.h"
 #include "loot/exception/git_state_error.h"
+#include "loot/exception/undefined_group_error.h"
 #include "loot/game_interface.h"
 #include "loot/loot_version.h"
 
diff --git a/include/loot/exception/undefined_group_error.h b/include/loot/exception/undefined_group_error.h
new file mode 100644
index 00000000..30e8208f
--- /dev/null
+++ b/include/loot/exception/undefined_group_error.h
@@ -0,0 +1,58 @@
+/*  LOOT
+
+    A load order optimisation tool for Oblivion, Skyrim, Fallout 3 and
+    Fallout: New Vegas.
+
+    Copyright (C) 2012-2016    WrinklyNinja
+
+    This file is part of LOOT.
+
+    LOOT is free software: you can redistribute
+    it and/or modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation, either version 3 of
+    the License, or (at your option) any later version.
+
+    LOOT is distributed in the hope that it will
+    be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with LOOT.  If not, see
+    <https://www.gnu.org/licenses/>.
+    */
+
+#ifndef LOOT_EXCEPTION_UNDEFINED_GROUP_ERROR
+#define LOOT_EXCEPTION_UNDEFINED_GROUP_ERROR
+
+#include <stdexcept>
+
+namespace loot {
+/**
+ * @brief An exception class thrown if group is referenced but is undefined.
+ */
+class UndefinedGroupError : public std::runtime_error {
+public:
+  /**
+   * @brief Construct an exception detailing a plugin graph cycle.
+   * @param firstPlugin A plugin in the cycle.
+   * @param lastPlugin Another plugin in the cycle.
+   * @param backCycle A string describing the path from lastPlugin to
+   *                  firstPlugin.
+   */
+  UndefinedGroupError(const std::string& groupName) :
+      std::runtime_error("The group \"" + groupName + "\" does not exist"),
+      groupName_(groupName) {}
+
+  /**
+   * Get the name of the undefined group.
+   * @return A group name.
+   */
+  std::string getGroupName() { return groupName_; }
+
+private:
+  const std::string groupName_;
+};
+}
+
+#endif
diff --git a/src/api/sorting/group_sort.cpp b/src/api/sorting/group_sort.cpp
index bb674249..d317f783 100644
--- a/src/api/sorting/group_sort.cpp
+++ b/src/api/sorting/group_sort.cpp
@@ -29,6 +29,7 @@
 #include <boost/graph/depth_first_search.hpp>
 
 #include "loot/exception/cyclic_interaction_error.h"
+#include "loot/exception/undefined_group_error.h"
 
 namespace loot {
 typedef boost::adjacency_list<boost::vecS,
@@ -104,7 +105,7 @@ std::unordered_map<std::string, std::unordered_set<std::string>> GetTransitiveAf
     for (const auto& otherGroupName : group.GetAfterGroups()) {
       auto otherVertex = groupVertices.find(otherGroupName);
       if (otherVertex == groupVertices.end()) {
-        throw std::invalid_argument("The group \"" + otherGroupName + "\" does not exist");
+        throw UndefinedGroupError(otherGroupName);
       }
 
       auto vertex = groupVertices[group.GetName()];
diff --git a/src/api/sorting/plugin_sorter.cpp b/src/api/sorting/plugin_sorter.cpp
index 033ab04a..2069b669 100644
--- a/src/api/sorting/plugin_sorter.cpp
+++ b/src/api/sorting/plugin_sorter.cpp
@@ -37,6 +37,7 @@
 #include "api/metadata/condition_evaluator.h"
 #include "api/sorting/group_sort.h"
 #include "loot/exception/cyclic_interaction_error.h"
+#include "loot/exception/undefined_group_error.h"
 
 using std::list;
 using std::string;
@@ -266,8 +267,7 @@ void PluginSorter::AddPluginVertices(Game& game) {
     PluginSortingData& plugin = graph_[vertex];
     auto groupsIt = groups.find(plugin.GetGroup());
     if (groupsIt == groups.end()) {
-      throw std::invalid_argument("The group \"" + plugin.GetGroup() +
-        "\" set for plugin \"" + plugin.GetName() + "\" does not exist.");
+      throw UndefinedGroupError(plugin.GetGroup());
     }
     else {
       plugin.SetAfterGroupPlugins(groupsIt->second);
diff --git a/src/tests/api/internals/sorting/group_sort_test.h b/src/tests/api/internals/sorting/group_sort_test.h
index ffd8144c..8056f4e8 100644
--- a/src/tests/api/internals/sorting/group_sort_test.h
+++ b/src/tests/api/internals/sorting/group_sort_test.h
@@ -30,6 +30,7 @@ along with LOOT.  If not, see
 #include <gtest/gtest.h>
 
 #include "loot/exception/cyclic_interaction_error.h"
+#include "loot/exception/undefined_group_error.h"
 
 namespace loot {
 namespace test {
@@ -52,7 +53,7 @@ TEST(GetTransitiveAfterGroups, shouldThrowIfAnAfterGroupDoesNotExist) {
     Group("b", std::unordered_set<std::string>({ "a" }))
   });
 
-  EXPECT_THROW(GetTransitiveAfterGroups(groups), std::invalid_argument);
+  EXPECT_THROW(GetTransitiveAfterGroups(groups), UndefinedGroupError);
 }
 
 TEST(GetTransitiveAfterGroups, shouldThrowIfAfterGroupsAreCyclic) {
diff --git a/src/tests/api/internals/sorting/plugin_sorter_test.h b/src/tests/api/internals/sorting/plugin_sorter_test.h
index 31c88599..fd3a423b 100644
--- a/src/tests/api/internals/sorting/plugin_sorter_test.h
+++ b/src/tests/api/internals/sorting/plugin_sorter_test.h
@@ -28,6 +28,7 @@ along with LOOT.  If not, see
 #include "api/sorting/plugin_sorter.h"
 
 #include "loot/exception/cyclic_interaction_error.h"
+#include "loot/exception/undefined_group_error.h"
 #include "tests/common_game_test_fixture.h"
 
 namespace loot {
@@ -207,7 +208,7 @@ TEST_P(PluginSorterTest, sortingShouldThrowIfAPluginHasAGroupThatDoesNotExist) {
   game_.GetDatabase()->SetPluginUserMetadata(plugin);
 
   PluginSorter ps;
-  EXPECT_THROW(ps.Sort(game_), std::invalid_argument);
+  EXPECT_THROW(ps.Sort(game_), UndefinedGroupError);
 }
 
 TEST_P(PluginSorterTest, sortingShouldThrowIfAddingTwoGroupEdgesIntroducesACycle) {