diff --git a/crates/polars-core/src/chunked_array/object/builder.rs b/crates/polars-core/src/chunked_array/object/builder.rs
index 351cdc58a383b..7b45079aafeb3 100644
--- a/crates/polars-core/src/chunked_array/object/builder.rs
+++ b/crates/polars-core/src/chunked_array/object/builder.rs
@@ -145,6 +145,7 @@ where
 }
 
 /// Convert a Series of dtype object to an Arrow Array of FixedSizeBinary
+#[cfg(feature = "algorithm_group_by")]
 pub(crate) fn object_series_to_arrow_array(s: &Series) -> ArrayRef {
     // The list builder knows how to create an arrow array
     // we simply piggy back on that code.
diff --git a/crates/polars-core/src/series/implementations/object.rs b/crates/polars-core/src/series/implementations/object.rs
index c58f37159d90a..6129cb39e654f 100644
--- a/crates/polars-core/src/series/implementations/object.rs
+++ b/crates/polars-core/src/series/implementations/object.rs
@@ -49,6 +49,8 @@ where
     fn _get_flags(&self) -> Settings {
         self.0.get_flags()
     }
+
+    #[cfg(feature = "algorithm_group_by")]
     unsafe fn agg_list(&self, groups: &GroupsProxy) -> Series {
         self.0.agg_list(groups)
     }
@@ -185,14 +187,17 @@ where
         ObjectChunked::has_validity(&self.0)
     }
 
+    #[cfg(feature = "algorithm_group_by")]
     fn unique(&self) -> PolarsResult<Series> {
         ChunkUnique::unique(&self.0).map(|ca| ca.into_series())
     }
 
+    #[cfg(feature = "algorithm_group_by")]
     fn n_unique(&self) -> PolarsResult<usize> {
         ChunkUnique::n_unique(&self.0)
     }
 
+    #[cfg(feature = "algorithm_group_by")]
     fn arg_unique(&self) -> PolarsResult<IdxCa> {
         ChunkUnique::arg_unique(&self.0)
     }
diff --git a/crates/polars-core/src/series/into.rs b/crates/polars-core/src/series/into.rs
index 9a8b03ed46905..48ad653e6363d 100644
--- a/crates/polars-core/src/series/into.rs
+++ b/crates/polars-core/src/series/into.rs
@@ -87,6 +87,7 @@ impl Series {
             #[cfg(feature = "dtype-time")]
             DataType::Time => cast(&*self.chunks()[chunk_idx], &DataType::Time.to_arrow()).unwrap(),
             #[cfg(feature = "object")]
+            #[cfg(feature = "algorithm_group_by")]
             DataType::Object(_) => {
                 use crate::chunked_array::object::builder::object_series_to_arrow_array;
                 if self.chunks().len() == 1 && chunk_idx == 0 {