diff --git a/MODULE.bazel b/MODULE.bazel
index dc6b56d18176d..2e2fc36bf3c36 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -29,7 +29,7 @@ bazel_dep(name = "abseil-cpp", version = "20250814.2")
 # The name "com_google_protobuf" is internally used by @bazel_tools,
 # a native repository we cannot override.
 # See https://github.com/googleapis/google-cloud-cpp/issues/15393
-bazel_dep(name = "protobuf", version = "35.1", repo_name = "com_google_protobuf")
+bazel_dep(name = "protobuf", version = "36.0-rc2", repo_name = "com_google_protobuf")
 bazel_dep(name = "boringssl", version = "0.20251124.0")
 bazel_dep(name = "nlohmann_json", version = "3.12.0.bcr.1")
 bazel_dep(name = "curl", version = "8.8.0.bcr.3")
diff --git a/bazel/workspace0.bzl b/bazel/workspace0.bzl
index b0e46039c6b51..45bc14612176c 100644
--- a/bazel/workspace0.bzl
+++ b/bazel/workspace0.bzl
@@ -171,10 +171,10 @@ def gl_cpp_workspace0(name = None):
         http_archive,
         name = "com_google_protobuf",
         urls = [
-            "https://github.com/protocolbuffers/protobuf/archive/v31.1.tar.gz",
+            "https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz",
         ],
-        sha256 = "c3a0a9ece8932e31c3b736e2db18b1c42e7070cd9b881388b26d01aa71e24ca2",
-        strip_prefix = "protobuf-31.1",
+        sha256 = "46f5c52302d4af9b4a02c0f7d495167c72b0225b99b2ac3938f857f2f51435c5",
+        strip_prefix = "protobuf-36.0-rc2",
     )
 
     # Load BoringSSL. This could be automatically loaded by gRPC. But as of
diff --git a/ci/cloudbuild/dockerfiles/demo-debian-bookworm.Dockerfile b/ci/cloudbuild/dockerfiles/demo-debian-bookworm.Dockerfile
index 8ba22402ecc73..8d3d8c0641c0c 100644
--- a/ci/cloudbuild/dockerfiles/demo-debian-bookworm.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-debian-bookworm.Dockerfile
@@ -76,7 +76,7 @@ RUN curl -fsSL https://github.com/abseil/abseil-cpp/archive/20250814.2.tar.gz |
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
diff --git a/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile b/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile
index fe357506bd3ce..3b8c9f3fde09a 100644
--- a/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile
@@ -68,7 +68,7 @@ RUN apt-get update && \
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
diff --git a/ci/cloudbuild/dockerfiles/demo-fedora.Dockerfile b/ci/cloudbuild/dockerfiles/demo-fedora.Dockerfile
index b544061a357ad..c69d4027f9248 100644
--- a/ci/cloudbuild/dockerfiles/demo-fedora.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-fedora.Dockerfile
@@ -66,7 +66,7 @@ ENV PKG_CONFIG_PATH=/usr/local/share/pkgconfig:/usr/lib64/pkgconfig:/usr/local/l
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/demo-opensuse-leap.Dockerfile b/ci/cloudbuild/dockerfiles/demo-opensuse-leap.Dockerfile
index df91fcc713bb2..3e9f56c100054 100644
--- a/ci/cloudbuild/dockerfiles/demo-opensuse-leap.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-opensuse-leap.Dockerfile
@@ -75,7 +75,7 @@ RUN curl -fsSL https://github.com/abseil/abseil-cpp/archive/20250814.2.tar.gz |
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
diff --git a/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile b/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile
index 607401c1f4336..69d72cb1c7ef2 100644
--- a/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile
@@ -93,7 +93,7 @@ RUN curl -fsSL https://github.com/abseil/abseil-cpp/archive/20250814.2.tar.gz |
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
diff --git a/ci/cloudbuild/dockerfiles/demo-ubuntu-24.04.Dockerfile b/ci/cloudbuild/dockerfiles/demo-ubuntu-24.04.Dockerfile
index b4a248130d2bd..f6033c174b8c1 100644
--- a/ci/cloudbuild/dockerfiles/demo-ubuntu-24.04.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-ubuntu-24.04.Dockerfile
@@ -78,7 +78,7 @@ RUN curl -fsSL https://github.com/abseil/abseil-cpp/archive/20250814.2.tar.gz |
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
diff --git a/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile b/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile
index 77addb40842e2..945a310a6c5b4 100644
--- a/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile
@@ -52,7 +52,7 @@ RUN curl -fsSL https://github.com/abseil/abseil-cpp/archive/20250814.2.tar.gz |
 
 # ```bash
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
diff --git a/ci/cloudbuild/dockerfiles/fedora-cmake-quickstart.Dockerfile b/ci/cloudbuild/dockerfiles/fedora-cmake-quickstart.Dockerfile
index b19cd5905fa49..7bde1d7100ceb 100644
--- a/ci/cloudbuild/dockerfiles/fedora-cmake-quickstart.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-cmake-quickstart.Dockerfile
@@ -129,7 +129,7 @@ RUN curl -fsSL https://github.com/nlohmann/json/archive/v3.11.3.tar.gz | \
     ldconfig && cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/fedora-latest-cmake.Dockerfile b/ci/cloudbuild/dockerfiles/fedora-latest-cmake.Dockerfile
index 59104b8e25e64..29fd16a5c6dfe 100644
--- a/ci/cloudbuild/dockerfiles/fedora-latest-cmake.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-latest-cmake.Dockerfile
@@ -129,7 +129,7 @@ RUN curl -fsSL https://github.com/nlohmann/json/archive/v3.11.3.tar.gz | \
     ldconfig && cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile b/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile
index e321e2b937c48..72da74b8a3bd2 100644
--- a/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile
@@ -125,7 +125,7 @@ RUN curl -fsSL https://github.com/nlohmann/json/archive/v3.11.3.tar.gz | \
     cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_CXX_STANDARD=20 \
diff --git a/ci/cloudbuild/dockerfiles/fedora-latest-publish-docs.Dockerfile b/ci/cloudbuild/dockerfiles/fedora-latest-publish-docs.Dockerfile
index a12b7d08dc146..6f61906d26921 100644
--- a/ci/cloudbuild/dockerfiles/fedora-latest-publish-docs.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-latest-publish-docs.Dockerfile
@@ -88,7 +88,7 @@ RUN curl -fsSL https://github.com/open-telemetry/opentelemetry-cpp/archive/v1.24
     ldconfig && cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile b/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile
index 9ff742c279af0..83b536ad55b77 100644
--- a/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile
@@ -84,7 +84,7 @@ RUN curl -fsSL https://github.com/google/benchmark/archive/v1.9.5.tar.gz | \
     ldconfig && cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/ubuntu-20.04-install.Dockerfile b/ci/cloudbuild/dockerfiles/ubuntu-20.04-install.Dockerfile
index 200a068bce1b0..04c896e723cdf 100644
--- a/ci/cloudbuild/dockerfiles/ubuntu-20.04-install.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/ubuntu-20.04-install.Dockerfile
@@ -110,7 +110,7 @@ RUN curl -fsSL https://github.com/nlohmann/json/archive/v3.11.3.tar.gz | \
 
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/ubuntu-22.04-install.Dockerfile b/ci/cloudbuild/dockerfiles/ubuntu-22.04-install.Dockerfile
index cfc7db4be552b..cb6f0404067e2 100644
--- a/ci/cloudbuild/dockerfiles/ubuntu-22.04-install.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/ubuntu-22.04-install.Dockerfile
@@ -109,7 +109,7 @@ RUN curl -fsSL https://github.com/nlohmann/json/archive/v3.11.3.tar.gz | \
 
 
 WORKDIR /var/tmp/build/protobuf
-RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/doc/packaging.md b/doc/packaging.md
index 3e00e72b6bc98..5e4992b5d267e 100644
--- a/doc/packaging.md
+++ b/doc/packaging.md
@@ -279,7 +279,7 @@ export PKG_CONFIG_PATH=/usr/local/share/pkgconfig:/usr/lib64/pkgconfig:/usr/loca
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
@@ -421,7 +421,7 @@ sudo ldconfig
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
@@ -594,7 +594,7 @@ sudo ldconfig
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
@@ -740,7 +740,7 @@ Google Cloud Platform proto files:
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
@@ -907,7 +907,7 @@ sudo ldconfig
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
@@ -1072,7 +1072,7 @@ to build from source:
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \
@@ -1249,7 +1249,7 @@ install Protobuf (and any downstream packages) from source.
 
 ```bash
 mkdir -p $HOME/Downloads/protobuf && cd $HOME/Downloads/protobuf
-curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v33.6.tar.gz | \
+curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v36.0-rc2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Debug \