diff --git a/NEWS.md b/NEWS.md
index f7e08809..98252a46 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # cpp11 (development version)
 
+* `cpp_register()` now also picks up a `{package}_types.h` or `{package}_types.hpp` in `src/include/`, letting a package keep that header private instead of installing it from `inst/include/`.
+
 # cpp11 0.5.5
 
 * Fixed an issue where `cpp11::stop()` and `cpp11::warning()` calls with the same template instantiation could cause a crash on some systems (#491, #295).
diff --git a/R/register.R b/R/register.R
index 68c7f585..6b9bbd73 100644
--- a/R/register.R
+++ b/R/register.R
@@ -114,17 +114,28 @@ cpp_register <- function(
     )
   }
 
+  pkg_types_name <- paste0(package, c("_types.h", "_types.hpp"))
+
   pkg_types <- c(
-    file.path(path, "src", paste0(package, "_types.h")),
-    file.path(path, "src", paste0(package, "_types.hpp")),
-    file.path(path, "inst", "include", paste0(package, "_types.h")),
-    file.path(path, "inst", "include", paste0(package, "_types.hpp"))
+    file.path(path, "src", pkg_types_name),
+    file.path(path, "src", "include", pkg_types_name),
+    file.path(path, "inst", "include", pkg_types_name)
+  )
+
+  # `src/cpp11.cpp` is generated next to the `src/` copies and compiled from
+  # `src/`, so a header in `src/include/` is included through that directory.
+  # A package keeping its own headers private this way then needs no include
+  # flag for them, and none of the other two locations changes.
+  pkg_types_include <- c(
+    pkg_types_name,
+    file.path("include", pkg_types_name),
+    pkg_types_name
   )
 
   pkg_types_exist <- file.exists(pkg_types)
   if (any(pkg_types_exist)) {
     extra_includes <- c(
-      sprintf('#include "%s"', basename(pkg_types[pkg_types_exist])),
+      sprintf('#include "%s"', pkg_types_include[pkg_types_exist]),
       extra_includes
     )
   }
diff --git a/tests/testthat/test-register.R b/tests/testthat/test-register.R
index 7f65bb8a..7e3c86b6 100644
--- a/tests/testthat/test-register.R
+++ b/tests/testthat/test-register.R
@@ -685,6 +685,50 @@ describe("cpp_register", {
     )
   })
 
+  it("includes pkg_types.h if included in src/include", {
+    pkg <- local_package()
+    p <- pkg_path(pkg)
+    dir.create(file.path(p, "src", "include"), recursive = TRUE)
+    file.copy(test_path("single.cpp"), file.path(p, "src", "single.cpp"))
+    writeLines(
+      "#include <sstream>",
+      file.path(p, "src", "include", "testPkg_types.h")
+    )
+    cpp_register(p)
+
+    expect_true(
+      any(
+        grepl(
+          pattern = '#include "include/testPkg_types.h"',
+          x = readLines(file.path(p, "src", "cpp11.cpp")),
+          fixed = TRUE
+        )
+      )
+    )
+  })
+
+  it("includes pkg_types.hpp if included in src/include", {
+    pkg <- local_package()
+    p <- pkg_path(pkg)
+    dir.create(file.path(p, "src", "include"), recursive = TRUE)
+    file.copy(test_path("single.cpp"), file.path(p, "src", "single.cpp"))
+    writeLines(
+      "#include <sstream>",
+      file.path(p, "src", "include", "testPkg_types.hpp")
+    )
+    cpp_register(p)
+
+    expect_true(
+      any(
+        grepl(
+          pattern = '#include "include/testPkg_types.hpp"',
+          x = readLines(file.path(p, "src", "cpp11.cpp")),
+          fixed = TRUE
+        )
+      )
+    )
+  })
+
   it("includes pkg_types.h if included in inst/include", {
     pkg <- local_package()
     p <- pkg_path(pkg)