diff --git a/Cargo.lock b/Cargo.lock
index 4fd68f9..325e361 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1790,9 +1790,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3"
-version = "0.26.0"
+version = "0.27.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7ba0117f4212101ee6544044dae45abe1083d30ce7b29c4b5cbdfa2354e07383"
+checksum = "37a6df7eab65fc7bee654a421404947e10a0f7085b6951bf2ea395f4659fb0cf"
 dependencies = [
  "indoc",
  "libc",
@@ -1808,18 +1808,18 @@ dependencies = [
 
 [[package]]
 name = "pyo3-build-config"
-version = "0.26.0"
+version = "0.27.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fc6ddaf24947d12a9aa31ac65431fb1b851b8f4365426e182901eabfb87df5f"
+checksum = "f77d387774f6f6eec64a004eac0ed525aab7fa1966d94b42f743797b3e395afb"
 dependencies = [
  "target-lexicon",
 ]
 
 [[package]]
 name = "pyo3-ffi"
-version = "0.26.0"
+version = "0.27.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "025474d3928738efb38ac36d4744a74a400c901c7596199e20e45d98eb194105"
+checksum = "2dd13844a4242793e02df3e2ec093f540d948299a6a77ea9ce7afd8623f542be"
 dependencies = [
  "libc",
  "pyo3-build-config",
@@ -1827,9 +1827,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros"
-version = "0.26.0"
+version = "0.27.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e64eb489f22fe1c95911b77c44cc41e7c19f3082fc81cce90f657cdc42ffded"
+checksum = "eaf8f9f1108270b90d3676b8679586385430e5c0bb78bb5f043f95499c821a71"
 dependencies = [
  "proc-macro2",
  "pyo3-macros-backend",
@@ -1839,9 +1839,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros-backend"
-version = "0.26.0"
+version = "0.27.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "100246c0ecf400b475341b8455a9213344569af29a3c841d29270e53102e0fcf"
+checksum = "70a3b2274450ba5288bc9b8c1b69ff569d1d61189d4bff38f8d22e03d17f932b"
 dependencies = [
  "heck 0.5.0",
  "proc-macro2",
diff --git a/py-nominal-streaming/Cargo.toml b/py-nominal-streaming/Cargo.toml
index 6b31bfa..f1d8d52 100644
--- a/py-nominal-streaming/Cargo.toml
+++ b/py-nominal-streaming/Cargo.toml
@@ -14,7 +14,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 # PyO3 with a stable ABI across Python 3.10+.
-pyo3 = { version = "0.26", features = ["extension-module", "abi3-py310", "time"] }
+pyo3 = { version = "0.27", features = ["extension-module", "abi3-py310", "time"] }
 
 nominal-api = { workspace = true }
 tokio = { workspace = true, features = ["rt-multi-thread", "time"] }