diff --git a/avogadro/core/CMakeLists.txt b/avogadro/core/CMakeLists.txt
index 04822bd55f..ec2dbcd32c 100644
--- a/avogadro/core/CMakeLists.txt
+++ b/avogadro/core/CMakeLists.txt
@@ -26,7 +26,7 @@ target_sources(Headers PUBLIC
     utilities.h
     vector.h
 )
-target_link_libraries(Headers INTERFACE Eigen3::Eigen3)
+target_link_libraries(Headers INTERFACE Eigen3::Eigen)
 install(TARGETS Headers
   EXPORT "AvogadroLibsTargets"
   FILE_SET HEADERS DESTINATION "${INSTALL_INCLUDE_DIR}")
diff --git a/cmake/FindEigen3.cmake b/cmake/FindEigen3.cmake
index 103690ed5a..45c40ac832 100644
--- a/cmake/FindEigen3.cmake
+++ b/cmake/FindEigen3.cmake
@@ -1,11 +1,11 @@
-find_path(Eigen3_INCLUDE_DIR
+find_path(EIGEN3_INCLUDE_DIR
   NAMES signature_of_eigen3_matrix_library
   PATH_SUFFIXES eigen3 eigen
   DOC "Eigen include directory")
-mark_as_advanced(Eigen3_INCLUDE_DIR)
+mark_as_advanced(EIGEN3_INCLUDE_DIR)
 
-if (Eigen3_INCLUDE_DIR)
-  file(STRINGS "${Eigen3_INCLUDE_DIR}/Eigen/src/Core/util/Macros.h" _Eigen3_version_lines
+if (EIGEN3_INCLUDE_DIR)
+  file(STRINGS "${EIGEN3_INCLUDE_DIR}/Eigen/src/Core/util/Macros.h" _Eigen3_version_lines
     REGEX "#define[ \t]+EIGEN_(WORLD|MAJOR|MINOR)_VERSION")
   string(REGEX REPLACE ".*EIGEN_WORLD_VERSION *\([0-9]*\).*" "\\1" _Eigen3_version_world "${_Eigen3_version_lines}")
   string(REGEX REPLACE ".*EIGEN_MAJOR_VERSION *\([0-9]*\).*" "\\1" _Eigen3_version_major "${_Eigen3_version_lines}")
@@ -19,15 +19,15 @@ endif ()
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(Eigen3
-  REQUIRED_VARS Eigen3_INCLUDE_DIR
-  VERSION_VAR Eigen3_VERSION)
+  REQUIRED_VARS EIGEN3_INCLUDE_DIR
+  VERSION_VAR EIGEN3_VERSION)
 
 if (Eigen3_FOUND)
-  set(Eigen3_INCLUDE_DIRS "${Eigen3_INCLUDE_DIR}")
+  set(Eigen3_INCLUDE_DIRS "${EIGEN3_INCLUDE_DIR}")
 
-  if (NOT TARGET Eigen3::Eigen3)
-    add_library(Eigen3::Eigen3 INTERFACE IMPORTED)
-    set_target_properties(Eigen3::Eigen3 PROPERTIES
-      INTERFACE_INCLUDE_DIRECTORIES "${Eigen3_INCLUDE_DIR}")
+  if (NOT TARGET Eigen3::Eigen)
+    add_library(Eigen3::Eigen INTERFACE IMPORTED)
+    set_target_properties(Eigen3::Eigen PROPERTIES
+      INTERFACE_INCLUDE_DIRECTORIES "${EIGEN3_INCLUDE_DIR}")
   endif ()
 endif ()
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c5d2c5e07c..8d4657531e 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -2,10 +2,12 @@ include_directories("${AvogadroLibs_BINARY_DIR}/avogadro/core")
 
 # find google test
 find_package(GTest REQUIRED)
+find_package(Eigen3 REQUIRED)
 # Add both as "system headers" to avoid warnings generated by them with
 # compilers that support that notion.
 include_directories(SYSTEM
-  ${GTEST_INCLUDE_DIRS})
+  ${GTEST_INCLUDE_DIRS}
+  ${EIGEN3_INCLUDE_DIR})
 
 include(CheckIncludeFileCXX)
 include(CheckCXXSymbolExists)
@@ -42,4 +44,3 @@ if(USE_OPENGL)
     add_subdirectory(qtopengl)
   endif()
 endif()
-