diff --git a/CHANGELOG.md b/CHANGELOG.md
index f72afbd4..805f9ee5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 
 ## Fixes
 - Enable a negative part_number for `split_part()` ([#557](https://github.com/dbt-labs/dbt-utils/issues/557), [#559](https://github.com/dbt-labs/dbt-utils/pull/559))
+- Make `exclude` case insensitive for `union_relations()` ([#578](https://github.com/dbt-labs/dbt-utils/issues/557), [#587](https://github.com/dbt-labs/dbt-utils/issues/587))
 
 ## Quality of life
 - Documentation about listagg macro ([#544](https://github.com/dbt-labs/dbt-utils/issues/544), [#560](https://github.com/dbt-labs/dbt-utils/pull/560))
@@ -21,6 +22,7 @@
 - [@clausherther](https://github.com/clausherther) (#555)
 - [@epapineau](https://github.com/epapineau) (#583)
 - [@b-per](https://github.com/b-per) (#559)
+- [@dbeatty10](https://github.com/dbeatty10), [@jeremyyeo](https://github.com/jeremyyeo) (#587)
 
 # dbt-utils v0.8.4
 ## Fixes
diff --git a/integration_tests/data/sql/data_union_exclude_expected.csv b/integration_tests/data/sql/data_union_exclude_expected.csv
new file mode 100644
index 00000000..3283e5c6
--- /dev/null
+++ b/integration_tests/data/sql/data_union_exclude_expected.csv
@@ -0,0 +1,6 @@
+id,favorite_color,favorite_number
+1,,pi
+2,,e
+3,,4
+1,"green",7
+2,"pink",13
diff --git a/integration_tests/models/sql/schema.yml b/integration_tests/models/sql/schema.yml
index e5927fbf..df10ccac 100644
--- a/integration_tests/models/sql/schema.yml
+++ b/integration_tests/models/sql/schema.yml
@@ -163,6 +163,16 @@ models:
         tests:
           - dbt_utils.not_constant
 
+  - name: test_union_exclude_lowercase
+    tests:
+      - dbt_utils.equality:
+          compare_model: ref('data_union_exclude_expected')
+
+  - name: test_union_exclude_uppercase
+    tests:
+      - dbt_utils.equality:
+          compare_model: ref('data_union_exclude_expected')
+
   - name: test_get_relations_by_pattern
     tests:
       - dbt_utils.equality:
diff --git a/integration_tests/models/sql/test_union_exclude_base_lowercase.sql b/integration_tests/models/sql/test_union_exclude_base_lowercase.sql
new file mode 100644
index 00000000..dc005a8e
--- /dev/null
+++ b/integration_tests/models/sql/test_union_exclude_base_lowercase.sql
@@ -0,0 +1,8 @@
+
+{{ dbt_utils.union_relations(
+    relations=[
+        ref('data_union_table_1'),
+        ref('data_union_table_2'),
+    ],
+    exclude=['name']
+) }}
diff --git a/integration_tests/models/sql/test_union_exclude_base_uppercase.sql b/integration_tests/models/sql/test_union_exclude_base_uppercase.sql
new file mode 100644
index 00000000..af3dc3fa
--- /dev/null
+++ b/integration_tests/models/sql/test_union_exclude_base_uppercase.sql
@@ -0,0 +1,8 @@
+
+{{ dbt_utils.union_relations(
+    relations=[
+        ref('data_union_table_1'),
+        ref('data_union_table_2'),
+    ],
+    exclude=['NAME']
+) }}
diff --git a/integration_tests/models/sql/test_union_exclude_lowercase.sql b/integration_tests/models/sql/test_union_exclude_lowercase.sql
new file mode 100644
index 00000000..95efc06a
--- /dev/null
+++ b/integration_tests/models/sql/test_union_exclude_lowercase.sql
@@ -0,0 +1,4 @@
+select
+    {{ dbt_utils.star(ref("test_union_exclude_base_lowercase"), except=["_dbt_source_relation"]) }}
+
+from {{ ref("test_union_exclude_base_lowercase") }}
diff --git a/integration_tests/models/sql/test_union_exclude_uppercase.sql b/integration_tests/models/sql/test_union_exclude_uppercase.sql
new file mode 100644
index 00000000..3e0ab4f9
--- /dev/null
+++ b/integration_tests/models/sql/test_union_exclude_uppercase.sql
@@ -0,0 +1,4 @@
+select
+    {{ dbt_utils.star(ref("test_union_exclude_base_uppercase"), except=["_DBT_SOURCE_RELATION"]) }}
+
+from {{ ref("test_union_exclude_base_uppercase") }}
diff --git a/macros/sql/union.sql b/macros/sql/union.sql
index 0d4ebccb..74bbd988 100644
--- a/macros/sql/union.sql
+++ b/macros/sql/union.sql
@@ -17,6 +17,20 @@
 
     {%- set relation_columns = {} -%}
     {%- set column_superset = {} -%}
+    {%- set all_excludes = [] -%}
+    {%- set all_includes = [] -%}
+
+    {%- if exclude -%}
+        {%- for exc in exclude -%}
+            {%- do all_excludes.append(exc | lower) -%}
+        {%- endfor -%}
+    {%- endif -%}
+
+    {%- if include -%}
+        {%- for inc in include -%}
+            {%- do all_includes.append(inc | lower) -%}
+        {%- endfor -%}
+    {%- endif -%}
 
     {%- for relation in relations -%}
 
@@ -28,10 +42,10 @@
         {%- for col in cols -%}
 
         {#- If an exclude list was provided and the column is in the list, do nothing -#}
-        {%- if exclude and col.column in exclude -%}
+        {%- if exclude and col.column | lower in all_excludes -%}
 
         {#- If an include list was provided and the column is not in the list, do nothing -#}
-        {%- elif include and col.column not in include -%}
+        {%- elif include and col.column | lower not in all_includes -%}
 
         {#- Otherwise add the column to the column superset -#}
         {%- else -%}