diff --git a/.changes/unreleased/Fixes-20230818-214616.yaml b/.changes/unreleased/Fixes-20230818-214616.yaml
new file mode 100644
index 000000000..a66059e21
--- /dev/null
+++ b/.changes/unreleased/Fixes-20230818-214616.yaml
@@ -0,0 +1,6 @@
+kind: Fixes
+body: case insensitive check on partition matching
+time: 2023-08-18T21:46:16.828488+02:00
+custom:
+  Author: Kayrnt
+  Issue: "886"
diff --git a/dbt/adapters/bigquery/__init__.py b/dbt/adapters/bigquery/__init__.py
index b66ef278a..adbd67590 100644
--- a/dbt/adapters/bigquery/__init__.py
+++ b/dbt/adapters/bigquery/__init__.py
@@ -2,7 +2,7 @@
 from dbt.adapters.bigquery.connections import BigQueryCredentials
 from dbt.adapters.bigquery.relation import BigQueryRelation  # noqa
 from dbt.adapters.bigquery.column import BigQueryColumn  # noqa
-from dbt.adapters.bigquery.impl import BigQueryAdapter, GrantTarget  # noqa
+from dbt.adapters.bigquery.impl import BigQueryAdapter, GrantTarget, PartitionConfig  # noqa
 
 from dbt.adapters.base import AdapterPlugin
 from dbt.include import bigquery
diff --git a/dbt/adapters/bigquery/impl.py b/dbt/adapters/bigquery/impl.py
index f53cd4084..3f8351861 100644
--- a/dbt/adapters/bigquery/impl.py
+++ b/dbt/adapters/bigquery/impl.py
@@ -620,12 +620,13 @@ def _partitions_match(table, conf_partition: Optional[PartitionConfig]) -> bool:
             table_field = (
                 table.time_partitioning.field.lower() if table.time_partitioning.field else None
             )
+
             table_granularity = table.partitioning_type
             conf_table_field = conf_partition.field
             return (
-                table_field == conf_table_field
+                table_field == conf_table_field.lower()
                 or (conf_partition.time_ingestion_partitioning and table_field is not None)
-            ) and table_granularity == conf_partition.granularity
+            ) and table_granularity.lower() == conf_partition.granularity.lower()
         elif conf_partition and table.range_partitioning is not None:
             dest_part = table.range_partitioning
             conf_part = conf_partition.range or {}
diff --git a/tests/unit/test_bigquery_adapter.py b/tests/unit/test_bigquery_adapter.py
index 56b8e07d7..bb98db86f 100644
--- a/tests/unit/test_bigquery_adapter.py
+++ b/tests/unit/test_bigquery_adapter.py
@@ -12,10 +12,12 @@
 
 import dbt.dataclass_schema
 
+from dbt.adapters.bigquery import PartitionConfig
 from dbt.adapters.bigquery import BigQueryCredentials
 from dbt.adapters.bigquery import BigQueryAdapter
 from dbt.adapters.bigquery import BigQueryRelation
 from dbt.adapters.bigquery import Plugin as BigQueryPlugin
+from google.cloud.bigquery.table import Table
 from dbt.adapters.bigquery.connections import BigQueryConnectionManager
 from dbt.adapters.bigquery.connections import _sanitize_label, _VALIDATE_LABEL_LENGTH_LIMIT
 from dbt.adapters.base.query_headers import MacroQueryStringSetter
@@ -376,7 +378,10 @@ def test_location_user_agent(self, mock_bq, mock_auth_default):
         mock_client.assert_not_called()
         connection.handle
         mock_client.assert_called_once_with(
-            "dbt-unit-000000", creds, location="Luna Station", client_info=HasUserAgent()
+            "dbt-unit-000000",
+            creds,
+            location="Luna Station",
+            client_info=HasUserAgent(),
         )
 
 
@@ -1023,6 +1028,30 @@ def test_convert_time_type(self):
         for col_idx, expect in enumerate(expected):
             assert BigQueryAdapter.convert_time_type(agate_table, col_idx) == expect
 
+    # The casing in this case can't be enforced on the API side,
+    # so we have to validate that we have a case-insensitive comparison
+    def test_partitions_match(self):
+        table = Table.from_api_repr(
+            {
+                "tableReference": {
+                    "projectId": "test-project",
+                    "datasetId": "test_dataset",
+                    "tableId": "test_table",
+                },
+                "timePartitioning": {"type": "DAY", "field": "ts"},
+            }
+        )
+        partition_config = PartitionConfig.parse(
+            {
+                "field": "TS",
+                "data_type": "date",
+                "granularity": "day",
+                "time_ingestion_partitioning": False,
+                "copy_partitions": False,
+            }
+        )
+        assert BigQueryAdapter._partitions_match(table, partition_config) is True
+
 
 class TestBigQueryGrantAccessTo(BaseTestBigQueryAdapter):
     entity = BigQueryRelation.from_dict(