diff --git a/c/driver/postgresql/postgresql_test.cc b/c/driver/postgresql/postgresql_test.cc
index 42e5df9056..4b060c47ed 100644
--- a/c/driver/postgresql/postgresql_test.cc
+++ b/c/driver/postgresql/postgresql_test.cc
@@ -2428,6 +2428,28 @@ TEST_F(PostgresStatementTest, BindUpsertWithSlicedListParameter) {
   ASSERT_THAT(AdbcStatementRelease(&statement, &error), IsOkStatus(&error));
 }
 
+// Regression test for https://github.com/apache/arrow-adbc/issues/4999.
+TEST_F(PostgresStatementTest, SqlQueryTrailingWhitespace) {
+  ASSERT_THAT(AdbcStatementNew(&connection, &statement, &error), IsOkStatus(&error));
+  ASSERT_THAT(AdbcStatementSetSqlQuery(&statement, "SELECT 1; \t\r\n", &error),
+              IsOkStatus(&error));
+
+  adbc_validation::StreamReader reader;
+  ASSERT_THAT(
+      AdbcStatementExecuteQuery(&statement, &reader.stream.value, nullptr, &error),
+      IsOkStatus(&error));
+  ASSERT_NO_FATAL_FAILURE(reader.GetSchema());
+  ASSERT_EQ(reader.schema->n_children, 1);
+  ASSERT_EQ(reader.fields[0].type, NANOARROW_TYPE_INT32);
+  ASSERT_NO_FATAL_FAILURE(reader.Next());
+  ASSERT_NE(reader.array->release, nullptr);
+  ASSERT_EQ(reader.array->length, 1);
+  ASSERT_NO_FATAL_FAILURE(
+      adbc_validation::CompareArray<int32_t>(reader.array_view->children[0], {1}));
+  ASSERT_NO_FATAL_FAILURE(reader.Next());
+  ASSERT_EQ(reader.array->release, nullptr);
+}
+
 TEST_F(PostgresStatementTest, SqlExecuteCopyZeroRowOutputError) {
   ASSERT_THAT(quirks()->DropTable(&connection, "adbc_test", &error), IsOkStatus(&error));
   ASSERT_THAT(AdbcStatementNew(&connection, &statement, &error), IsOkStatus(&error));
diff --git a/c/driver/postgresql/result_helper.cc b/c/driver/postgresql/result_helper.cc
index 95a686730f..52285237a7 100644
--- a/c/driver/postgresql/result_helper.cc
+++ b/c/driver/postgresql/result_helper.cc
@@ -111,8 +111,10 @@ Status PqResultHelper::Execute(const std::vector<std::string>& params,
 }
 
 Status PqResultHelper::ExecuteCopy() {
-  // Remove trailing semicolon(s) from the query before feeding it into COPY
-  while (!query_.empty() && query_.back() == ';') {
+  // Remove trailing semicolons and whitespace before feeding the query into COPY
+  while (!query_.empty() &&
+         (query_.back() == ';' || query_.back() == ' ' || query_.back() == '\t' ||
+          query_.back() == '\r' || query_.back() == '\n')) {
     query_.pop_back();
   }