diff --git a/Cargo.toml b/Cargo.toml
index b85cdb0..0ff6980 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,7 @@ authors = ["Kyle Cesare <kcesare@gmail.com>"]
 version = "0.3.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
+rust-version = "1.65"
 
 [profile.release]
 lto = "fat"
diff --git a/crates/optik-cpp/Cargo.toml b/crates/optik-cpp/Cargo.toml
index df63606..d6aa5b6 100644
--- a/crates/optik-cpp/Cargo.toml
+++ b/crates/optik-cpp/Cargo.toml
@@ -4,6 +4,7 @@ authors.workspace = true
 version.workspace = true
 edition.workspace = true
 license.workspace = true
+rust-version.workspace = true
 
 [lib]
 name = "optikcpp"
diff --git a/crates/optik-py/Cargo.toml b/crates/optik-py/Cargo.toml
index 24fdb0f..343af88 100644
--- a/crates/optik-py/Cargo.toml
+++ b/crates/optik-py/Cargo.toml
@@ -4,6 +4,7 @@ authors.workspace = true
 version.workspace = true
 edition.workspace = true
 license.workspace = true
+rust-version.workspace = true
 
 [lib]
 name = "optik"
diff --git a/crates/optik/Cargo.toml b/crates/optik/Cargo.toml
index 27a6ca4..eefefa6 100644
--- a/crates/optik/Cargo.toml
+++ b/crates/optik/Cargo.toml
@@ -4,6 +4,7 @@ authors.workspace = true
 version.workspace = true
 edition.workspace = true
 license.workspace = true
+rust-version.workspace = true
 
 [lib]
 name = "optik"