diff --git a/cmake/OpenEXRSetup.cmake b/cmake/OpenEXRSetup.cmake
index 3a31710e0..01ad5960e 100644
--- a/cmake/OpenEXRSetup.cmake
+++ b/cmake/OpenEXRSetup.cmake
@@ -219,10 +219,13 @@ else()
     message(STATUS "libdeflate was not found, installing from ${OPENEXR_DEFLATE_REPO} (${OPENEXR_DEFLATE_TAG})")
   endif()
   include(FetchContent)
+  # Fetch deflate but exclude it from the "all" target.
+  # This prevents the library from being built.
   FetchContent_Declare(Deflate
     GIT_REPOSITORY "${OPENEXR_DEFLATE_REPO}"
     GIT_TAG "${OPENEXR_DEFLATE_TAG}"
     GIT_SHALLOW ON
+    EXCLUDE_FROM_ALL
     )
 
   FetchContent_GetProperties(Deflate)
@@ -230,6 +233,20 @@ else()
     FetchContent_MakeAvailable(Deflate)
   endif()
 
+  if(CMAKE_VERSION VERSION_LESS "3.28")
+    # Prior to CMake 3.28, passing the EXCLUDE_FROM_ALL option to
+    # FetchContent_Declare() does *not* have the desired effect of
+    # excluding the fetched content from the build when
+    # FetchContent_MakeAvailable() is called, so we "manually"
+    # exclude it for those CMake versions.
+    if(IS_DIRECTORY "${deflate_SOURCE_DIR}")
+      set_property(DIRECTORY ${deflate_SOURCE_DIR} PROPERTY EXCLUDE_FROM_ALL YES)
+    endif()
+    if(IS_DIRECTORY "${deflate_BINARY_DIR}")
+      set_property(DIRECTORY ${deflate_BINARY_DIR} PROPERTY EXCLUDE_FROM_ALL YES)
+    endif()
+  endif()
+
   # Rather than actually compile something, just embed the sources
   # into exrcore. This could in theory cause issues when compiling as
   # a static library into another application which also uses