diff --git a/.changes/unreleased/Fixes-20230320-153225.yaml b/.changes/unreleased/Fixes-20230320-153225.yaml
new file mode 100644
index 00000000000..be49986203f
--- /dev/null
+++ b/.changes/unreleased/Fixes-20230320-153225.yaml
@@ -0,0 +1,6 @@
+kind: Fixes
+body: add negative part_number arg for split part macro
+time: 2023-03-20T15:32:25.5932-05:00
+custom:
+  Author: dave-connors-3
+  Issue: "7915"
diff --git a/core/dbt/include/global_project/macros/utils/split_part.sql b/core/dbt/include/global_project/macros/utils/split_part.sql
index cecc4497b58..766539ac0c1 100644
--- a/core/dbt/include/global_project/macros/utils/split_part.sql
+++ b/core/dbt/include/global_project/macros/utils/split_part.sql
@@ -20,7 +20,7 @@
           length({{ string_text }})
           - length(
               replace({{ string_text }},  {{ delimiter_text }}, '')
-          ) + 2 {{ part_number }}
+          ) + 2 + {{ part_number }}
         )
 
 {% endmacro %}
diff --git a/tests/adapter/dbt/tests/adapter/utils/fixture_split_part.py b/tests/adapter/dbt/tests/adapter/utils/fixture_split_part.py
index 7fc70e5bf54..244fbdb7464 100644
--- a/tests/adapter/dbt/tests/adapter/utils/fixture_split_part.py
+++ b/tests/adapter/dbt/tests/adapter/utils/fixture_split_part.py
@@ -1,9 +1,9 @@
 # split_part
 
-seeds__data_split_part_csv = """parts,split_on,result_1,result_2,result_3
-a|b|c,|,a,b,c
-1|2|3,|,1,2,3
-,|,,,
+seeds__data_split_part_csv = """parts,split_on,result_1,result_2,result_3,result_4
+a|b|c,|,a,b,c,c
+1|2|3,|,1,2,3,3
+,|,,,,
 """
 
 
@@ -34,6 +34,14 @@
     {{ split_part('parts', 'split_on', 3) }} as actual,
     result_3 as expected
 
+from data
+
+union all
+
+select
+    {{ split_part('parts', 'split_on', -1) }} as actual,
+    result_4 as expected
+
 from data
 """