diff --git a/CHANGELOG.md b/CHANGELOG.md
index ab2db27c85..82eaf5a2ba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,6 +52,9 @@ Increment the:
 * [BUILD] Upgrade nlohmann_json to 3.12.0
   [#3406](https://github.com/open-telemetry/opentelemetry-cpp/pull/3406)
 
+* [CMAKE] Add generated protobuf headers to the opentelemetry_proto target
+  [#3400](https://github.com/open-telemetry/opentelemetry-cpp/pull/3400)
+
 ## [1.20 2025-04-01]
 
 * [BUILD] Update opentelemetry-proto version
diff --git a/cmake/opentelemetry-proto.cmake b/cmake/opentelemetry-proto.cmake
index 246a41e5d5..60b3472845 100644
--- a/cmake/opentelemetry-proto.cmake
+++ b/cmake/opentelemetry-proto.cmake
@@ -290,8 +290,6 @@ add_custom_command(
   COMMENT "[Run]: ${PROTOBUF_RUN_PROTOC_COMMAND}"
   DEPENDS ${PROTOBUF_PROTOC_EXECUTABLE})
 
-include_directories("${GENERATED_PROTOBUF_PATH}")
-
 unset(OTELCPP_PROTO_TARGET_OPTIONS)
 if(CMAKE_SYSTEM_NAME MATCHES "Windows|MinGW|WindowsStore")
   list(APPEND OTELCPP_PROTO_TARGET_OPTIONS STATIC)
@@ -315,6 +313,11 @@ add_library(
   ${METRICS_SERVICE_PB_CPP_FILE})
 set_target_version(opentelemetry_proto)
 
+target_include_directories(
+  opentelemetry_proto
+  PUBLIC "$<BUILD_INTERFACE:${GENERATED_PROTOBUF_PATH}>"
+         "$<INSTALL_INTERFACE:include>")
+
 # Disable include-what-you-use on generated code.
 set_target_properties(opentelemetry_proto PROPERTIES CXX_INCLUDE_WHAT_YOU_USE
                                                      "")
diff --git a/third_party/nlohmann-json b/third_party/nlohmann-json
index 55f93686c0..9cca280a4d 160000
--- a/third_party/nlohmann-json
+++ b/third_party/nlohmann-json
@@ -1 +1 @@
-Subproject commit 55f93686c01528224f448c19128836e7df245f72
+Subproject commit 9cca280a4d0ccf0c08f47a99aa71d1b0e52f8d03