diff --git a/CMakeLists.txt b/CMakeLists.txt
index 366e86f9..fdaa5546 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -221,6 +221,11 @@ ADD_COMPILE_DEFINITIONS(JFJOCH_USE_FFTW)
 SET(EIGEN_BUILD_DOC OFF CACHE BOOL "" FORCE)
 SET(EIGEN_BUILD_TESTING OFF CACHE BOOL "" FORCE)
 SET(EIGEN_BUILD_PKGCONFIG OFF CACHE BOOL "" FORCE)
+# Ceres' install(EXPORT CeresExport) is unconditional and its ceres target transitively links the
+# eigen target, so eigen must live in an installed export set or generation fails ("eigen is not in
+# any export set"). As a subproject Eigen defaults EIGEN_BUILD_CMAKE_PACKAGE OFF, which skips its
+# install(EXPORT Eigen3Targets); force it ON so eigen is exported and Ceres' export resolves.
+SET(EIGEN_BUILD_CMAKE_PACKAGE ON CACHE BOOL "" FORCE)
 FetchContent_Declare(Eigen3
         GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
         GIT_TAG 5.0.1