diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 295461aad634cddc99ff84aeeb8dc2733b0562c1..20afe311fefb0a5ece7a87345e62c5cace0971be 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -81,7 +81,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
       - uses: matrix-org/setup-python-poetry@v1
         with:
@@ -148,7 +148,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
 
       - name: Setup Poetry
@@ -208,7 +208,7 @@ jobs:
         with:
           ref: ${{ github.event.pull_request.head.sha }}
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
       - uses: matrix-org/setup-python-poetry@v1
         with:
@@ -225,7 +225,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
         with:
             components: clippy
       - uses: Swatinem/rust-cache@v2
@@ -344,7 +344,7 @@ jobs:
             postgres:${{ matrix.job.postgres-version }}
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
 
       - uses: matrix-org/setup-python-poetry@v1
@@ -386,7 +386,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
 
       # There aren't wheels for some of the older deps, so we need to install
@@ -498,7 +498,7 @@ jobs:
         run: cat sytest-blacklist .ci/worker-blacklist > synapse-blacklist-with-workers
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
 
       - name: Run SyTest
@@ -642,7 +642,7 @@ jobs:
           path: synapse
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
 
       - name: Prepare Complement's Prerequisites
@@ -674,7 +674,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@1.65.0
+        uses: dtolnay/rust-toolchain@1.66.0
       - uses: Swatinem/rust-cache@v2
 
       - run: cargo test
diff --git a/changelog.d/17079.misc b/changelog.d/17079.misc
new file mode 100644
index 0000000000000000000000000000000000000000..340e40d1946da6e89429ca5bd3063f7e075f028c
--- /dev/null
+++ b/changelog.d/17079.misc
@@ -0,0 +1 @@
+Bump minimum supported Rust version to 1.66.0.
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index d89def1843a15064158e3c7ce66d75fc91b27cf7..ba293f8d4fe2360d6b2f0b7b85369f644f4d321c 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -7,7 +7,7 @@ name = "synapse"
 version = "0.1.0"
 
 edition = "2021"
-rust-version = "1.65.0"
+rust-version = "1.66.0"
 
 [lib]
 name = "synapse"