diff --git a/sqlit/domains/connections/providers/oracle/adapter.py b/sqlit/domains/connections/providers/oracle/adapter.py
index 76edc895..2f0503c5 100644
--- a/sqlit/domains/connections/providers/oracle/adapter.py
+++ b/sqlit/domains/connections/providers/oracle/adapter.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import re
 from typing import TYPE_CHECKING, Any
 
 from sqlit.domains.connections.providers.adapters.base import (
@@ -18,6 +19,31 @@
     from sqlit.domains.connections.domain.config import ConnectionConfig
 
 
+_LEADING_SQL_COMMENTS = re.compile(
+    r"^\s*(?:(?:--[^\n]*(?:\n|$))|(?:/\*.*?\*/\s*))*",
+    re.DOTALL,
+)
+_PLSQL_START = re.compile(
+    r"^(?:BEGIN|DECLARE)\b|^CREATE\s+(?:OR\s+REPLACE\s+)?"
+    r"(?:(?:NON)?EDITIONABLE\s+)?"
+    r"(?:FUNCTION|PACKAGE|PROCEDURE|TRIGGER|TYPE\s+BODY)\b",
+    re.IGNORECASE,
+)
+
+
+def _prepare_statement(query: str) -> str:
+    """Remove SQL*Plus terminators that python-oracledb does not accept."""
+    statement = query.rstrip()
+    if not statement.endswith(";"):
+        return query
+
+    without_leading_comments = _LEADING_SQL_COMMENTS.sub("", statement)
+    if _PLSQL_START.match(without_leading_comments):
+        return query
+
+    return statement[:-1].rstrip()
+
+
 class OracleAdapter(DatabaseAdapter):
     """Adapter for Oracle Database using oracledb.
 
@@ -339,7 +365,7 @@ def execute_query(self, conn: Any, query: str, max_rows: int | None = None) -> t
         """Execute a query on Oracle with optional row limit."""
         cursor = conn.cursor()
         try:
-            cursor.execute(query)
+            cursor.execute(_prepare_statement(query))
             if cursor.description:
                 columns = [col[0] for col in cursor.description]
                 if max_rows is not None:
@@ -359,7 +385,7 @@ def execute_non_query(self, conn: Any, query: str) -> int:
         """Execute a non-query on Oracle."""
         cursor = conn.cursor()
         try:
-            cursor.execute(query)
+            cursor.execute(_prepare_statement(query))
             rowcount = int(cursor.rowcount)
             conn.commit()
             return rowcount
diff --git a/tests/connections/providers/oracle/test_statement_execution.py b/tests/connections/providers/oracle/test_statement_execution.py
new file mode 100644
index 00000000..73eda739
--- /dev/null
+++ b/tests/connections/providers/oracle/test_statement_execution.py
@@ -0,0 +1,77 @@
+"""Oracle-specific statement execution behavior."""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from sqlit.domains.connections.providers.oracle.adapter import OracleAdapter
+
+
+@pytest.fixture
+def adapter() -> OracleAdapter:
+    return OracleAdapter()
+
+
+@pytest.fixture
+def mock_conn() -> MagicMock:
+    conn = MagicMock()
+    cursor = conn.cursor.return_value
+    cursor.description = None
+    cursor.rowcount = 0
+    return conn
+
+
+@pytest.mark.parametrize(
+    ("query", "expected"),
+    [
+        ("SELECT ';' AS value FROM DUAL;", "SELECT ';' AS value FROM DUAL"),
+        ("SELECT 1 FROM DUAL;  \n", "SELECT 1 FROM DUAL"),
+        ("SELECT 1 FROM DUAL", "SELECT 1 FROM DUAL"),
+    ],
+)
+def test_execute_query_removes_sql_statement_terminator(
+    adapter: OracleAdapter,
+    mock_conn: MagicMock,
+    query: str,
+    expected: str,
+) -> None:
+    """python-oracledb rejects SQL statements ending in a semicolon."""
+    adapter.execute_query(mock_conn, query)
+
+    mock_conn.cursor.return_value.execute.assert_called_once_with(expected)
+
+
+def test_execute_non_query_removes_sql_statement_terminator(
+    adapter: OracleAdapter,
+    mock_conn: MagicMock,
+) -> None:
+    """Issue #260: ALTER SESSION must reach python-oracledb without ``;``."""
+    adapter.execute_non_query(mock_conn, "ALTER SESSION SET EDITION = V0;")
+
+    mock_conn.cursor.return_value.execute.assert_called_once_with("ALTER SESSION SET EDITION = V0")
+
+
+@pytest.mark.parametrize(
+    "statement",
+    [
+        "BEGIN NULL; END;",
+        "DECLARE value NUMBER := 1; BEGIN NULL; END;",
+        "CREATE OR REPLACE PROCEDURE p AS BEGIN NULL; END;",
+        "-- setup\nBEGIN NULL; END;",
+        "/* setup */ CREATE OR REPLACE EDITIONABLE FUNCTION f RETURN NUMBER "
+        "AS BEGIN RETURN 1; END;",
+        "CREATE OR REPLACE TYPE BODY t AS MEMBER PROCEDURE p IS "
+        "BEGIN NULL; END; END;",
+    ],
+)
+def test_execute_non_query_preserves_plsql_terminator(
+    adapter: OracleAdapter,
+    mock_conn: MagicMock,
+    statement: str,
+) -> None:
+    """The final semicolon is part of PL/SQL syntax, not a client terminator."""
+    adapter.execute_non_query(mock_conn, statement)
+
+    mock_conn.cursor.return_value.execute.assert_called_once_with(statement)