diff --git a/bazel/workspace0.bzl b/bazel/workspace0.bzl
index f5fde679d0469..1e0ce82c7f4d3 100644
--- a/bazel/workspace0.bzl
+++ b/bazel/workspace0.bzl
@@ -161,10 +161,10 @@ def gl_cpp_workspace0(name = None):
         http_archive,
         name = "com_github_grpc_grpc",
         urls = [
-            "https://github.com/grpc/grpc/archive/v1.65.2.tar.gz",
+            "https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz",
         ],
-        sha256 = "0ff2e0a6abf195cf23b4ce808570bcbb2ff4b5bee453af0b45afd496e661f2c0",
-        strip_prefix = "grpc-1.65.2",
+        sha256 = "7de9753e789d4335a0b5d44b390afcf3e5581eb0a86a561afbb3f0b68051063f",
+        strip_prefix = "grpc-1.66.0-pre1",
     )
 
     # We use the cc_proto_library() rule from @com_google_protobuf, which
diff --git a/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile b/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile
index 64e536601dc31..b0351784a4e02 100644
--- a/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-debian-bullseye.Dockerfile
@@ -125,7 +125,7 @@ RUN curl -fsSL https://github.com/google/re2/archive/2024-07-02.tar.gz | \
 
 # ```bash
 WORKDIR /var/tmp/build/grpc
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile b/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile
index e1ab0c67d6b3a..06c9434dad3d7 100644
--- a/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-rockylinux-9.Dockerfile
@@ -128,7 +128,7 @@ RUN curl -fsSL https://github.com/google/re2/archive/2024-07-02.tar.gz | \
 
 # ```bash
 WORKDIR /var/tmp/build/grpc
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_CXX_STANDARD=17 \
diff --git a/ci/cloudbuild/dockerfiles/demo-ubuntu-focal.Dockerfile b/ci/cloudbuild/dockerfiles/demo-ubuntu-focal.Dockerfile
index 32053a338ce7d..1b9c1b650c587 100644
--- a/ci/cloudbuild/dockerfiles/demo-ubuntu-focal.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-ubuntu-focal.Dockerfile
@@ -95,7 +95,7 @@ RUN curl -fsSL https://github.com/google/re2/archive/2024-07-02.tar.gz | \
 
 # ```bash
 WORKDIR /var/tmp/build/grpc
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile b/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile
index a76b16ddcd93f..535c3f322c708 100644
--- a/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/demo-ubuntu-jammy.Dockerfile
@@ -76,7 +76,7 @@ RUN curl -fsSL https://github.com/protocolbuffers/protobuf/archive/v27.2.tar.gz
 
 # ```bash
 WORKDIR /var/tmp/build/grpc
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.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 5c928c53850e8..32a7ed73af5c2 100644
--- a/ci/cloudbuild/dockerfiles/fedora-latest-cmake.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-latest-cmake.Dockerfile
@@ -160,7 +160,7 @@ RUN curl -fsSL https://github.com/open-telemetry/opentelemetry-cpp/archive/v1.16
 
 WORKDIR /var/tmp/build/grpc
 RUN dnf makecache && dnf install -y c-ares-devel re2-devel
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
       -DCMAKE_BUILD_TYPE=Release \
diff --git a/ci/cloudbuild/dockerfiles/fedora-latest-cxx14.Dockerfile b/ci/cloudbuild/dockerfiles/fedora-latest-cxx14.Dockerfile
index 1a7631c998ef1..03aee0115efe3 100644
--- a/ci/cloudbuild/dockerfiles/fedora-latest-cxx14.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-latest-cxx14.Dockerfile
@@ -168,7 +168,7 @@ RUN curl -fsSL https://github.com/open-telemetry/opentelemetry-cpp/archive/v1.16
 
 WORKDIR /var/tmp/build/grpc
 RUN dnf makecache && dnf install -y c-ares-devel re2-devel
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_CXX_STANDARD=14 \
diff --git a/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile b/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile
index e9bf881cadc99..7ce043a938dd9 100644
--- a/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/fedora-latest-cxx20.Dockerfile
@@ -170,7 +170,7 @@ RUN curl -fsSL https://github.com/open-telemetry/opentelemetry-cpp/archive/v1.16
 
 WORKDIR /var/tmp/build/grpc
 RUN dnf makecache && dnf install -y c-ares-devel re2-devel
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_CXX_STANDARD=20 \
diff --git a/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile b/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile
index 09770cbd671b1..b462304676b63 100644
--- a/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/gcc-oldest.Dockerfile
@@ -87,7 +87,7 @@ RUN curl -fsSL https://github.com/open-telemetry/opentelemetry-cpp/archive/v1.16
     ldconfig && cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/grpc
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.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 205837cacb7d2..eb5646650a84b 100644
--- a/ci/cloudbuild/dockerfiles/ubuntu-20.04-install.Dockerfile
+++ b/ci/cloudbuild/dockerfiles/ubuntu-20.04-install.Dockerfile
@@ -174,7 +174,7 @@ RUN curl -fsSL https://github.com/open-telemetry/opentelemetry-cpp/archive/v1.16
     ldconfig && cd /var/tmp && rm -fr build
 
 WORKDIR /var/tmp/build/grpc
-RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+RUN curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
diff --git a/doc/packaging.md b/doc/packaging.md
index 14a965fd78904..a28ab30a64cb3 100644
--- a/doc/packaging.md
+++ b/doc/packaging.md
@@ -607,7 +607,7 @@ Platform proto files. We install it using:
 
 ```bash
 mkdir -p $HOME/Downloads/grpc && cd $HOME/Downloads/grpc
-curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
@@ -794,7 +794,7 @@ Platform proto files. We install it using:
 
 ```bash
 mkdir -p $HOME/Downloads/grpc && cd $HOME/Downloads/grpc
-curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
@@ -1122,7 +1122,7 @@ Finally, we build gRPC from source:
 
 ```bash
 mkdir -p $HOME/Downloads/grpc && cd $HOME/Downloads/grpc
-curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
@@ -1301,7 +1301,7 @@ install it using:
 
 ```bash
 mkdir -p $HOME/Downloads/grpc && cd $HOME/Downloads/grpc
-curl -fsSL https://github.com/grpc/grpc/archive/v1.65.2.tar.gz | \
+curl -fsSL https://github.com/grpc/grpc/archive/v1.66.0-pre1.tar.gz | \
     tar -xzf - --strip-components=1 && \
     cmake \
         -DCMAKE_CXX_STANDARD=17 \