diff --git a/backend/scripts/__init__.py b/backend/scripts/__init__.py
new file mode 100644
index 0000000..7994ee4
--- /dev/null
+++ b/backend/scripts/__init__.py
@@ -0,0 +1 @@
+# Scripts package
diff --git a/backend/scripts/backfill_pypi_dependencies.py b/backend/scripts/backfill_pypi_dependencies.py
new file mode 100644
index 0000000..48194b7
--- /dev/null
+++ b/backend/scripts/backfill_pypi_dependencies.py
@@ -0,0 +1,262 @@
+#!/usr/bin/env python3
+"""
+Backfill script to extract dependencies from cached PyPI packages.
+
+This script scans all artifacts in the _pypi project and extracts
+Requires-Dist metadata from wheel and sdist files that don't already
+have dependencies recorded.
+
+Usage:
+    # From within the container:
+    python -m scripts.backfill_pypi_dependencies
+
+    # Or with docker exec:
+    docker exec orchard_orchard-server_1 python -m scripts.backfill_pypi_dependencies
+
+    # Dry run (preview only):
+    docker exec orchard_orchard-server_1 python -m scripts.backfill_pypi_dependencies --dry-run
+"""
+
+import argparse
+import logging
+import re
+import sys
+import tarfile
+import zipfile
+from io import BytesIO
+from typing import List, Optional, Tuple
+
+# Add parent directory to path for imports
+sys.path.insert(0, "/app")
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from backend.app.config import get_settings
+from backend.app.models import (
+    Artifact,
+    ArtifactDependency,
+    Package,
+    Project,
+    Tag,
+)
+from backend.app.storage import get_storage
+
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s - %(levelname)s - %(message)s",
+)
+logger = logging.getLogger(__name__)
+
+
+def parse_requires_dist(requires_dist: str) -> Tuple[Optional[str], Optional[str]]:
+    """Parse a Requires-Dist line into (package_name, version_constraint)."""
+    # Remove any environment markers (after semicolon)
+    if ";" in requires_dist:
+        requires_dist = requires_dist.split(";")[0].strip()
+
+    # Match patterns like "package (>=1.0)" or "package>=1.0" or "package"
+    match = re.match(
+        r"^([a-zA-Z0-9][-a-zA-Z0-9._]*)\s*(?:\(([^)]+)\)|([<>=!~][^\s;]+))?",
+        requires_dist.strip(),
+    )
+
+    if not match:
+        return None, None
+
+    package_name = match.group(1)
+    version_constraint = match.group(2) or match.group(3)
+
+    # Normalize package name (PEP 503)
+    normalized_name = re.sub(r"[-_.]+", "-", package_name).lower()
+
+    if version_constraint:
+        version_constraint = version_constraint.strip()
+
+    return normalized_name, version_constraint
+
+
+def extract_requires_from_metadata(metadata_content: str) -> List[Tuple[str, Optional[str]]]:
+    """Extract all Requires-Dist entries from METADATA/PKG-INFO content."""
+    dependencies = []
+
+    for line in metadata_content.split("\n"):
+        if line.startswith("Requires-Dist:"):
+            value = line[len("Requires-Dist:"):].strip()
+            pkg_name, version = parse_requires_dist(value)
+            if pkg_name:
+                dependencies.append((pkg_name, version))
+
+    return dependencies
+
+
+def extract_metadata_from_wheel(content: bytes) -> Optional[str]:
+    """Extract METADATA file content from a wheel (zip) file."""
+    try:
+        with zipfile.ZipFile(BytesIO(content)) as zf:
+            for name in zf.namelist():
+                if name.endswith(".dist-info/METADATA"):
+                    return zf.read(name).decode("utf-8", errors="replace")
+    except Exception as e:
+        logger.warning(f"Failed to extract metadata from wheel: {e}")
+    return None
+
+
+def extract_metadata_from_sdist(content: bytes) -> Optional[str]:
+    """Extract PKG-INFO file content from a source distribution (.tar.gz)."""
+    try:
+        with tarfile.open(fileobj=BytesIO(content), mode="r:gz") as tf:
+            for member in tf.getmembers():
+                if member.name.endswith("/PKG-INFO") and member.name.count("/") == 1:
+                    f = tf.extractfile(member)
+                    if f:
+                        return f.read().decode("utf-8", errors="replace")
+    except Exception as e:
+        logger.warning(f"Failed to extract metadata from sdist: {e}")
+    return None
+
+
+def extract_dependencies(content: bytes, filename: str) -> List[Tuple[str, Optional[str]]]:
+    """Extract dependencies from a PyPI package file."""
+    metadata = None
+
+    if filename.endswith(".whl"):
+        metadata = extract_metadata_from_wheel(content)
+    elif filename.endswith(".tar.gz"):
+        metadata = extract_metadata_from_sdist(content)
+
+    if metadata:
+        return extract_requires_from_metadata(metadata)
+
+    return []
+
+
+def backfill_dependencies(dry_run: bool = False):
+    """Main backfill function."""
+    settings = get_settings()
+
+    # Create database connection
+    engine = create_engine(settings.database_url)
+    Session = sessionmaker(bind=engine)
+    db = Session()
+
+    # Create storage client
+    storage = get_storage()
+
+    try:
+        # Find the _pypi project
+        pypi_project = db.query(Project).filter(Project.name == "_pypi").first()
+        if not pypi_project:
+            logger.info("No _pypi project found. Nothing to backfill.")
+            return
+
+        # Get all packages in _pypi
+        packages = db.query(Package).filter(Package.project_id == pypi_project.id).all()
+        logger.info(f"Found {len(packages)} packages in _pypi project")
+
+        total_artifacts = 0
+        artifacts_with_deps = 0
+        artifacts_processed = 0
+        dependencies_added = 0
+
+        for package in packages:
+            # Get all tags (each tag points to an artifact)
+            tags = db.query(Tag).filter(Tag.package_id == package.id).all()
+
+            for tag in tags:
+                total_artifacts += 1
+                filename = tag.name
+
+                # Skip non-package files (like .metadata files)
+                if not (filename.endswith(".whl") or filename.endswith(".tar.gz")):
+                    continue
+
+                # Check if this artifact already has dependencies
+                existing_deps = db.query(ArtifactDependency).filter(
+                    ArtifactDependency.artifact_id == tag.artifact_id
+                ).count()
+
+                if existing_deps > 0:
+                    artifacts_with_deps += 1
+                    continue
+
+                # Get the artifact
+                artifact = db.query(Artifact).filter(Artifact.id == tag.artifact_id).first()
+                if not artifact:
+                    logger.warning(f"Artifact {tag.artifact_id} not found for tag {filename}")
+                    continue
+
+                logger.info(f"Processing {package.name}/{filename}...")
+
+                if dry_run:
+                    logger.info(f"  [DRY RUN] Would extract dependencies from {filename}")
+                    artifacts_processed += 1
+                    continue
+
+                # Download the artifact from S3
+                try:
+                    content = storage.get(artifact.s3_key)
+                except Exception as e:
+                    logger.error(f"  Failed to download {filename}: {e}")
+                    continue
+
+                # Extract dependencies
+                deps = extract_dependencies(content, filename)
+
+                if deps:
+                    logger.info(f"  Found {len(deps)} dependencies")
+                    for dep_name, dep_version in deps:
+                        # Check if already exists (race condition protection)
+                        existing = db.query(ArtifactDependency).filter(
+                            ArtifactDependency.artifact_id == tag.artifact_id,
+                            ArtifactDependency.dependency_project == "_pypi",
+                            ArtifactDependency.dependency_package == dep_name,
+                        ).first()
+
+                        if not existing:
+                            dep = ArtifactDependency(
+                                artifact_id=tag.artifact_id,
+                                dependency_project="_pypi",
+                                dependency_package=dep_name,
+                                version_constraint=dep_version if dep_version else "*",
+                            )
+                            db.add(dep)
+                            dependencies_added += 1
+                            logger.info(f"    + {dep_name} {dep_version or '*'}")
+
+                    db.commit()
+                else:
+                    logger.info(f"  No dependencies found")
+
+                artifacts_processed += 1
+
+        logger.info("")
+        logger.info("=" * 50)
+        logger.info("Backfill complete!")
+        logger.info(f"  Total artifacts: {total_artifacts}")
+        logger.info(f"  Already had deps: {artifacts_with_deps}")
+        logger.info(f"  Processed: {artifacts_processed}")
+        logger.info(f"  Dependencies added: {dependencies_added}")
+        if dry_run:
+            logger.info("  (DRY RUN - no changes made)")
+
+    finally:
+        db.close()
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Backfill dependencies for cached PyPI packages"
+    )
+    parser.add_argument(
+        "--dry-run",
+        action="store_true",
+        help="Preview what would be done without making changes",
+    )
+    args = parser.parse_args()
+
+    backfill_dependencies(dry_run=args.dry_run)
+
+
+if __name__ == "__main__":
+    main()