diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9cbc9e3..6963703 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Added
 
 - Source distribution to PyPI publish ([#92](https://github.com/stac-utils/rustac-py/pull/92))
+- `rustac.sha` ([#99](https://github.com/stac-utils/rustac-py/pull/99))
 
 ### Fixed
 
diff --git a/Cargo.lock b/Cargo.lock
index 471a23a..68fde0a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -685,6 +685,18 @@ version = "1.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d71b6127be86fdcfddb610f7182ac57211d4b18a3e9c82eb2d17662f2227ad6a"
 
+[[package]]
+name = "cargo-lock"
+version = "10.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c06acb4f71407ba205a07cb453211e0e6a67b21904e47f6ba1f9589e38f2e454"
+dependencies = [
+ "semver",
+ "serde",
+ "toml",
+ "url",
+]
+
 [[package]]
 name = "cast"
 version = "0.3.0"
@@ -3453,6 +3465,7 @@ dependencies = [
 name = "rustac"
 version = "0.6.0"
 dependencies = [
+ "cargo-lock",
  "clap",
  "geoarrow",
  "geojson",
@@ -3637,6 +3650,9 @@ name = "semver"
 version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56e6fa9c48d24d85fb3de5ad847117517440f6beceb7798af16b4a87d616b8d0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "seq-macro"
@@ -3687,6 +3703,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_spanned"
+version = "0.6.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87607cb1398ed59d48732e575a4c28a7a8ebf2454b964fe3f224f2afc07909e1"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_urlencoded"
 version = "0.7.1"
@@ -4258,11 +4283,26 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "toml"
+version = "0.8.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd87a5cdd6ffab733b2f74bc4fd7ee5fff6634124999ac278c35fc78c6120148"
+dependencies = [
+ "serde",
+ "serde_spanned",
+ "toml_datetime",
+ "toml_edit",
+]
+
 [[package]]
 name = "toml_datetime"
 version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0dd7358ecb8fc2f8d014bf86f6f638ce72ba252a2c3a2572f2a795f1d23efb41"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "toml_edit"
@@ -4271,6 +4311,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "17b4795ff5edd201c7cd6dca065ae59972ce77d1b80fa0a84d94950ece7d1474"
 dependencies = [
  "indexmap",
+ "serde",
+ "serde_spanned",
  "toml_datetime",
  "winnow",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 244a704..12ec2e0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -41,6 +41,9 @@ tokio = { version = "1.44.0", features = ["rt-multi-thread"] }
 pyo3-log = "0.12.1"
 tracing = "0.1.41"
 
+[build-dependencies]
+cargo-lock = "10"
+
 [patch.crates-io]
 # TODO unpatch cql2 when we upgrade geoarrow to use geo v0.30
 cql2 = { git = "https://github.com/gadomski/cql2-rs", branch = "geo-v0.29" }
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..028ce4c
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,12 @@
+use cargo_lock::Lockfile;
+
+fn main() {
+    let lockfile = Lockfile::load("Cargo.lock").unwrap();
+    let package = lockfile
+        .packages
+        .into_iter()
+        .find(|package| package.name.as_str() == "rustac")
+        .unwrap();
+    let precise = package.source.unwrap().precise().unwrap().to_string();
+    println!("cargo:rustc-env=RUSTAC_SHA={}", precise);
+}
diff --git a/docs/api/version.md b/docs/api/version.md
index 5453ae0..d501861 100644
--- a/docs/api/version.md
+++ b/docs/api/version.md
@@ -4,4 +4,5 @@ description: Return this package's version or the version of an upstream
 
 # Version
 
+::: rustac.sha
 ::: rustac.version
diff --git a/rustac.pyi b/rustac.pyi
index ffd2322..aa76584 100644
--- a/rustac.pyi
+++ b/rustac.pyi
@@ -453,3 +453,12 @@ def version(
         >>> rustac.version("duckdb")
         "1.0.0"
     """
+
+def sha() -> str:
+    """
+    Returns the SHA of the underlying rustac crate.
+
+    Examples:
+        >>> rustac.sha()
+        "4d6a60a3df1386922285191aba95a76ec704a8b4"
+    """
diff --git a/src/lib.rs b/src/lib.rs
index af1b973..5b970d8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -31,6 +31,7 @@ fn rustac(py: Python<'_>, m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(read::read, m)?)?;
     m.add_function(wrap_pyfunction!(search::search, m)?)?;
     m.add_function(wrap_pyfunction!(search::search_to, m)?)?;
+    m.add_function(wrap_pyfunction!(version::sha, m)?)?;
     m.add_function(wrap_pyfunction!(version::version, m)?)?;
     m.add_function(wrap_pyfunction!(walk::walk, m)?)?;
     m.add_function(wrap_pyfunction!(write::write, m)?)?;
diff --git a/src/version.rs b/src/version.rs
index 74a42ec..8712592 100644
--- a/src/version.rs
+++ b/src/version.rs
@@ -17,3 +17,9 @@ pub fn version(name: Option<String>) -> Option<String> {
         Some(env!("CARGO_PKG_VERSION").to_string())
     }
 }
+
+#[pyfunction]
+pub fn sha() -> String {
+    // This environment variable is set in the build script
+    env!("RUSTAC_SHA").to_string()
+}
diff --git a/tests/test_version.py b/tests/test_version.py
index 9b81804..ace63ab 100644
--- a/tests/test_version.py
+++ b/tests/test_version.py
@@ -6,3 +6,7 @@ def test_version() -> None:
     assert rustac.version("stac") is not None
     assert rustac.version("stac-api") is not None
     assert rustac.version("stac-duckdb") is not None
+
+
+def test_sha() -> None:
+    assert rustac.sha() is not None