diff --git a/python/Cargo.lock b/python/Cargo.lock
index 4ca113d45..fa67a0130 100644
--- a/python/Cargo.lock
+++ b/python/Cargo.lock
@@ -3695,6 +3695,20 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "sparrow-batch"
+version = "0.11.0"
+dependencies = [
+ "arrow",
+ "arrow-array",
+ "arrow-schema",
+ "arrow-select",
+ "derive_more",
+ "error-stack",
+ "itertools 0.11.0",
+ "static_init",
+]
+
 [[package]]
 name = "sparrow-compiler"
 version = "0.11.0"
@@ -3724,6 +3738,7 @@ dependencies = [
  "sparrow-core",
  "sparrow-instructions",
  "sparrow-merge",
+ "sparrow-sources",
  "sparrow-syntax",
  "static_init",
  "strum 0.25.0",
@@ -3784,6 +3799,18 @@ dependencies = [
  "uuid 1.4.1",
 ]
 
+[[package]]
+name = "sparrow-interfaces"
+version = "0.11.0"
+dependencies = [
+ "arrow-schema",
+ "derive_more",
+ "error-stack",
+ "futures",
+ "sparrow-batch",
+ "sparrow-core",
+]
+
 [[package]]
 name = "sparrow-kernels"
 version = "0.11.0"
@@ -3912,6 +3939,7 @@ dependencies = [
  "sparrow-instructions",
  "sparrow-merge",
  "sparrow-runtime",
+ "sparrow-sources",
  "sparrow-syntax",
  "static_init",
  "tempfile",
@@ -3920,6 +3948,24 @@ dependencies = [
  "uuid 1.4.1",
 ]
 
+[[package]]
+name = "sparrow-sources"
+version = "0.11.0"
+dependencies = [
+ "arrow-array",
+ "arrow-schema",
+ "async-broadcast",
+ "async-stream",
+ "derive_more",
+ "error-stack",
+ "futures",
+ "sparrow-batch",
+ "sparrow-core",
+ "sparrow-interfaces",
+ "sparrow-merge",
+ "tracing",
+]
+
 [[package]]
 name = "sparrow-syntax"
 version = "0.11.0"
diff --git a/python/pytests/execution_test.py b/python/pytests/execution_test.py
index afa53e4de..a987c944e 100644
--- a/python/pytests/execution_test.py
+++ b/python/pytests/execution_test.py
@@ -34,7 +34,7 @@ async def test_iter_pandas(golden, source_int64) -> None:
         next(batches)
 
 
-async def test_iter_rows(golden, source_int64) -> None:
+async def test_iter_rows(source_int64) -> None:
     results: Iterator[dict] = source_int64.run_iter("row", row_limit=2)
     assert next(results)["m"] == 5
     assert next(results)["m"] == 24
@@ -42,6 +42,19 @@ async def test_iter_rows(golden, source_int64) -> None:
         next(results)
 
 
+@kd.udf("add_one<N: number>(x: N) -> N")
+def add_one(x: pd.Series) -> pd.Series:
+    """Use Pandas to one"""
+    print("In UDF")
+    return x + 1
+
+
+async def test_iter_udf(source_int64) -> None:
+    results = source_int64.col("m").pipe(add_one).run_iter("row", row_limit=2)
+    assert next(results)["result"] == 6
+    assert next(results)["result"] == 25
+
+
 async def test_iter_pandas_async(golden, source_int64) -> None:
     batches: AsyncIterator[pd.DataFrame] = source_int64.run_iter(
         row_limit=4, max_batch_size=2
diff --git a/python/src/execution.rs b/python/src/execution.rs
index 5f38063be..c042c10c2 100644
--- a/python/src/execution.rs
+++ b/python/src/execution.rs
@@ -73,7 +73,11 @@ impl Execution {
 
     fn next_pyarrow(&mut self, py: Python<'_>) -> Result<Option<PyObject>> {
         let mut execution = self.execution()?;
-        let batch = execution.as_mut().unwrap().next_blocking()?;
+
+        // Explicitly allow threads to take the gil during execution, so
+        // the udf evaluator can acquire it to execute python.
+        let batch = py.allow_threads(move || execution.as_mut().unwrap().next_blocking())?;
+
         let result = match batch {
             Some(batch) => Some(batch.to_pyarrow(py)?),
             None => None,