diff --git a/cpp/src/groupby/sort/group_reductions.hpp b/cpp/src/groupby/sort/group_reductions.hpp
index 75708c7b01c..268c088fe87 100644
--- a/cpp/src/groupby/sort/group_reductions.hpp
+++ b/cpp/src/groupby/sort/group_reductions.hpp
@@ -173,6 +173,26 @@ std::unique_ptr<column> group_argmin(column_view const& values,
                                      rmm::cuda_stream_view stream,
                                      rmm::mr::device_memory_resource* mr);
 
+/**
+ * @brief Internal API to calculate group-wise indices of minimum/maximum values, specialized for
+ * STRUCT type.
+ *
+ * @param K The aggregation kind, must be `aggregation::ARGMIN` or `aggregation::ARGMAX`
+ * @param values Grouped values to get minimum value's index from
+ * @param num_groups Number of groups
+ * @param group_labels ID of group that the corresponding value belongs to
+ * @param key_sort_order Indices indicating sort order of groupby keys
+ * @param stream CUDA stream used for device memory operations and kernel launches.
+ * @param mr Device memory resource used to allocate the returned column's device memory
+ */
+std::unique_ptr<column> group_argminmax_struct(aggregation::Kind K,
+                                               column_view const& values,
+                                               size_type num_groups,
+                                               cudf::device_span<size_type const> group_labels,
+                                               column_view const& key_sort_order,
+                                               rmm::cuda_stream_view stream,
+                                               rmm::mr::device_memory_resource* mr);
+
 /**
  * @brief Internal API to calculate number of non-null values in each group of
  *  @p values
diff --git a/cpp/src/groupby/sort/group_scan.hpp b/cpp/src/groupby/sort/group_scan.hpp
index 82ef0e25380..2be779b6f3b 100644
--- a/cpp/src/groupby/sort/group_scan.hpp
+++ b/cpp/src/groupby/sort/group_scan.hpp
@@ -72,6 +72,24 @@ std::unique_ptr<column> max_scan(column_view const& values,
                                  rmm::cuda_stream_view stream,
                                  rmm::mr::device_memory_resource* mr);
 
+/**
+ * @brief Internal API to calculate groupwise cumulative minimum/maximum value, specialized for
+ * STRUCT type.
+ *
+ * @param K The aggregation kind, must be `aggregation::MIN` or `aggregation::MAX`
+ * @param values Grouped values to get maximum from
+ * @param num_groups Number of groups
+ * @param group_labels ID of group that the corresponding value belongs to
+ * @param stream CUDA stream used for device memory operations and kernel launches
+ * @param mr Device memory resource used to allocate the returned column's device memory
+ */
+std::unique_ptr<column> minmax_scan_struct(aggregation::Kind K,
+                                           column_view const& values,
+                                           size_type num_groups,
+                                           device_span<size_type const> group_labels,
+                                           rmm::cuda_stream_view stream,
+                                           rmm::mr::device_memory_resource* mr);
+
 /**
  * @brief Internal API to calculate cumulative number of values in each group
  *