diff --git a/breadbox/breadbox/api/dataset_uploads.py b/breadbox/breadbox/api/dataset_uploads.py
index 5c176c31c..f22cba5d4 100644
--- a/breadbox/breadbox/api/dataset_uploads.py
+++ b/breadbox/breadbox/api/dataset_uploads.py
@@ -1,6 +1,7 @@
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi.encoders import jsonable_encoder
 from breadbox.compute.dataset_uploads_tasks import run_dataset_upload
+from ..schemas.custom_http_exception import UserError
 
 from ..schemas.dataset import DatasetParams, AddDatasetResponse
 from .dependencies import get_user
@@ -64,6 +65,12 @@ def add_dataset_uploads(
         - `col_type`: Annotation type for the column. Annotation types may include: `continuous`, `categorical`, `text`, or `list_strings`
 
     """
+
+    if not dataset.is_transient and dataset.expiry_in_seconds is not None:
+        raise UserError(
+            "Dataset was not marked as 'transient' but expiry_in_seconds is set."
+        )
+
     # Converts a data type (like a Pydantic model) to something compatible with JSON, in this case a dict. Although Celery uses a JSON serializer to serialize arguments to tasks by default, pydantic models are too complex for their default serializer. Pydantic models have a built-in .dict() method but it turns out it doesn't convert enums to strings which celery can't JSON serialize, so I opted to use fastapi's jsonable_encoder() which appears to successfully json serialize enums
     dataset_json = jsonable_encoder(dataset)
     result = run_dataset_upload.delay(dataset_json, user)  # pyright: ignore
diff --git a/breadbox/breadbox/commands.py b/breadbox/breadbox/commands.py
index b8ea68397..7af22e06c 100644
--- a/breadbox/breadbox/commands.py
+++ b/breadbox/breadbox/commands.py
@@ -9,6 +9,7 @@
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 
+from breadbox.crud.dataset import find_expired_datasets, delete_dataset
 from breadbox.db.session import SessionWithUser
 from breadbox.config import Settings, get_settings
 from breadbox.crud.access_control import PUBLIC_GROUP_ID, TRANSIENT_GROUP_ID
@@ -26,6 +27,7 @@
 import shutil
 from db_load import upload_example_datasets
 import hashlib
+from datetime import timedelta
 
 
 @click.group()
@@ -33,6 +35,27 @@ def cli():
     pass
 
 
+@cli.command()
+@click.option("--dryrun", is_flag=True, default=False)
+@click.option("--maxdays", default=60, type=int)
+def delete_expired_datasets(maxdays, dryrun):
+    db = _get_db_connection()
+    settings = get_settings()
+    expired_datasets = find_expired_datasets(db, timedelta(days=maxdays))
+
+    print(f"Found {len(expired_datasets)} expired datasets")
+
+    with transaction(db):
+        for dataset in expired_datasets:
+            dataset_summary = f"{dataset.id} (upload_date={dataset.upload_date}, expiry={dataset.expiry})"
+            if dryrun:
+                print(f"dryrun: Would have deleted {dataset_summary}")
+            else:
+                print(f"Deleting {dataset_summary}")
+                delete_dataset(db, db.user, dataset, settings.filestore_location)
+    print("Done")
+
+
 @cli.command()
 @click.argument("user_email")
 @click.argument("group_name")
diff --git a/breadbox/breadbox/compute/analysis_tasks.py b/breadbox/breadbox/compute/analysis_tasks.py
index a903624fb..9ed3b9de9 100644
--- a/breadbox/breadbox/compute/analysis_tasks.py
+++ b/breadbox/breadbox/compute/analysis_tasks.py
@@ -482,6 +482,7 @@ def create_cell_line_group(
                 taiga_id=None,
                 dataset_metadata=None,
                 dataset_md5=None,
+                expiry=None,
             )
             dataset_service.add_matrix_dataset(
                 db,
diff --git a/breadbox/breadbox/compute/dataset_tasks.py b/breadbox/breadbox/compute/dataset_tasks.py
index 07022b0c0..a95102b1a 100644
--- a/breadbox/breadbox/compute/dataset_tasks.py
+++ b/breadbox/breadbox/compute/dataset_tasks.py
@@ -262,6 +262,7 @@ def upload_dataset(
         allowed_values=valid_fields.valid_allowed_values,
         dataset_metadata=dataset_metadata,
         dataset_md5=None,
+        expiry=None,
     )
 
     added_dataset = dataset_service.add_matrix_dataset(
diff --git a/breadbox/breadbox/compute/dataset_uploads_tasks.py b/breadbox/breadbox/compute/dataset_uploads_tasks.py
index 1b5414ae4..97a0cc32d 100644
--- a/breadbox/breadbox/compute/dataset_uploads_tasks.py
+++ b/breadbox/breadbox/compute/dataset_uploads_tasks.py
@@ -1,3 +1,4 @@
+from datetime import timedelta
 from uuid import UUID, uuid4
 from typing import Any, List, Optional, Union, Literal, Dict
 
@@ -81,6 +82,12 @@ def dataset_upload(
     )
 
     dataset_id = str(uuid4())
+    expiry = None
+    if dataset_params.expiry_in_seconds is not None:
+        assert dataset_params.is_transient
+        expiry = dataset_crud.get_current_datetime() + timedelta(
+            seconds=dataset_params.expiry_in_seconds
+        )
 
     unknown_ids = []
 
@@ -132,6 +139,7 @@ def dataset_upload(
             sample_type_name=dataset_params.sample_type,
             data_type=dataset_params.data_type,
             is_transient=dataset_params.is_transient,
+            expiry=expiry,
             group_id=str(dataset_params.group_id),
             value_type=dataset_params.value_type,
             priority=dataset_params.priority,
@@ -186,6 +194,7 @@ def dataset_upload(
             index_type_name=dataset_params.index_type,
             data_type=dataset_params.data_type,
             is_transient=dataset_params.is_transient,
+            expiry=expiry,
             group_id=str(dataset_params.group_id),
             priority=dataset_params.priority,
             taiga_id=dataset_params.taiga_id,
diff --git a/breadbox/breadbox/crud/dataset.py b/breadbox/breadbox/crud/dataset.py
index 418c57c49..cd91c6873 100644
--- a/breadbox/breadbox/crud/dataset.py
+++ b/breadbox/breadbox/crud/dataset.py
@@ -1,5 +1,6 @@
 import logging
 from collections import defaultdict
+from datetime import datetime, timedelta
 from typing import Any, Dict, Optional, List, Type, Union, Tuple, Set
 from uuid import UUID, uuid4
 import warnings
@@ -680,6 +681,35 @@ def update_dataset(
     return dataset
 
 
+def get_current_datetime():
+    # this method only exists to allow us to mock it in tests. Since `datetime` is a built-in we're not able to
+    # mutate it.
+    return datetime.now()
+
+
+def find_expired_datasets(db: SessionWithUser, max_age: timedelta) -> List[Dataset]:
+    """
+    Finds transient datasets which can be deleted (because they've "expired") 
+    Two ways a transient dataset can be expired: 
+    1. the `expiry` field can be explictly set, and that time is in the past
+    2. the upload_date is before now - `max_age`. 
+    """
+
+    now = get_current_datetime()
+    min_upload_date = now - max_age
+
+    expired_datasets = (
+        db.query(Dataset)
+        .filter(
+            Dataset.is_transient == True,
+            or_(Dataset.expiry < now, Dataset.upload_date < min_upload_date,),
+        )
+        .all()
+    )
+
+    return expired_datasets
+
+
 def delete_dataset(
     db: SessionWithUser, user: str, dataset: Dataset, filestore_location: str
 ):
diff --git a/breadbox/breadbox/models/dataset.py b/breadbox/breadbox/models/dataset.py
index 8937f2edd..f414af3d2 100644
--- a/breadbox/breadbox/models/dataset.py
+++ b/breadbox/breadbox/models/dataset.py
@@ -93,7 +93,13 @@ class Dataset(Base, UUIDMixin, GroupMixin):
     data_type: Mapped[str] = mapped_column(
         String, ForeignKey(DataType.data_type), nullable=False
     )
+
     is_transient: Mapped[bool] = mapped_column(Boolean, nullable=False)
+    # only meaningful for datasets where is_transient==True. Indicates when a transient dataset
+    # should be deleted.
+    expiry: Mapped[Optional[DateTime]] = mapped_column(
+        DateTime(timezone=True), nullable=True
+    )
 
     priority: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
     taiga_id: Mapped[Optional[str]] = mapped_column(String, nullable=True)
diff --git a/breadbox/breadbox/schemas/dataset.py b/breadbox/breadbox/schemas/dataset.py
index 1f662b91c..59455549c 100644
--- a/breadbox/breadbox/schemas/dataset.py
+++ b/breadbox/breadbox/schemas/dataset.py
@@ -9,7 +9,7 @@
 from breadbox.schemas.custom_http_exception import UserError
 from .group import Group
 import enum
-
+from datetime import datetime
 
 # NOTE: Using multivalue Literals seems to be creating errors in pydantic models and fastapi request params.
 # It is possible that for our version of pydantic, the schema for Literals is messed up
@@ -106,6 +106,12 @@ class SharedDatasetParams(BaseModel):
             description="Transient datasets can be deleted - should only be set to true for non-public short-term-use datasets like custom analysis results.",
         ),
     ] = False
+    expiry_in_seconds: Annotated[
+        Optional[int],
+        Field(
+            description="The number of seconds before this dataset is expired (only applies to transient datasets)"
+        ),
+    ] = None
     dataset_metadata: Annotated[
         Optional[Dict[str, Any]],
         Body(
@@ -286,6 +292,7 @@ class SharedDatasetFields(BaseModel):
     priority: Annotated[Optional[int], Field(default=None, gt=0,)]
     taiga_id: Annotated[Optional[str], Field(default=None,)]
     is_transient: Annotated[bool, Field(default=False,)]
+    expiry: Annotated[Optional[datetime], Field(default=None,)]
     dataset_metadata: Annotated[
         Optional[Dict[str, Any]], Field()
     ]  # NOTE: Same as Dict[str, Any] =  Field(None,)
diff --git a/breadbox/breadbox/service/dataset.py b/breadbox/breadbox/service/dataset.py
index 456b7a81e..55207754f 100644
--- a/breadbox/breadbox/service/dataset.py
+++ b/breadbox/breadbox/service/dataset.py
@@ -29,7 +29,11 @@
     get_transient_group,
 )
 
-from ..crud.dataset import add_tabular_dimensions, add_matrix_dataset_dimensions
+from ..crud.dataset import (
+    add_tabular_dimensions,
+    add_matrix_dataset_dimensions,
+    get_current_datetime,
+)
 from ..crud.dimension_types import (
     set_properties_to_index,
     add_metadata_dimensions,
@@ -354,6 +358,7 @@ def add_tabular_dataset(
         index_type_name=dataset_in.index_type_name,
         data_type=dataset_in.data_type,
         is_transient=dataset_in.is_transient,
+        expiry=dataset_in.expiry,
         group_id=group.id,
         priority=dataset_in.priority,
         taiga_id=dataset_in.taiga_id,
@@ -362,6 +367,7 @@ def add_tabular_dataset(
         short_name=short_name,
         version=version,
         description=description,
+        upload_date=get_current_datetime(),
     )
     db.add(dataset)
     db.flush()
@@ -421,6 +427,7 @@ def add_matrix_dataset(
         sample_type_name=dataset_in.sample_type_name,
         data_type=dataset_in.data_type,
         is_transient=dataset_in.is_transient,
+        expiry=dataset_in.expiry,
         group_id=group.id,
         value_type=dataset_in.value_type,
         priority=dataset_in.priority,
@@ -431,6 +438,7 @@ def add_matrix_dataset(
         short_name=short_name,
         description=description,
         version=version,
+        upload_date=get_current_datetime(),
     )
     db.add(dataset)
     db.flush()
@@ -500,6 +508,7 @@ def add_dimension_type(
             priority=None,
             dataset_metadata=None,
             dataset_md5=None,  # This may change!
+            expiry=None,
         )
 
         check_id_mapping_is_valid(db, reference_column_mappings)
diff --git a/breadbox/tests/api/test_dataset_uploads.py b/breadbox/tests/api/test_dataset_uploads.py
index 09e831ba4..ebd3928cc 100644
--- a/breadbox/tests/api/test_dataset_uploads.py
+++ b/breadbox/tests/api/test_dataset_uploads.py
@@ -1,4 +1,5 @@
 import io
+from datetime import datetime
 
 from fastapi.testclient import TestClient
 
@@ -6,14 +7,24 @@
 from breadbox.schemas.dataset import AddDatasetResponse
 from breadbox.compute import dataset_uploads_tasks
 from breadbox.celery_task import utils
-from breadbox.models.dataset import TabularDataset, TabularCell, TabularColumn
+from breadbox.models.dataset import TabularDataset, TabularCell, TabularColumn, Dataset
 from sqlalchemy import and_
+from datetime import timedelta
 
 from typing import Dict
-from ..utils import assert_status_ok
 import pytest
 import numpy as np
 from ..utils import upload_and_get_file_ids
+import json
+import pandas as pd
+from breadbox.models.dataset import AnnotationType
+from fastapi.testclient import TestClient
+from breadbox.schemas.dataset import ColumnMetadata
+from breadbox.crud.access_control import PUBLIC_GROUP_ID, TRANSIENT_GROUP_ID
+from tests import factories
+from ..utils import assert_status_not_ok, assert_status_ok
+from breadbox.crud import dataset as dataset_crud
+from breadbox.service import dataset as dataset_service
 
 
 class TestPost:
@@ -1166,13 +1177,94 @@ def test_add_tabular_dataset_with_invalid_list_str_vals(
         assert tabular_dataset.status_code == 400
 
 
-import json
-import pandas as pd
-from breadbox.models.dataset import AnnotationType
-from fastapi.testclient import TestClient
-from breadbox.schemas.dataset import ColumnMetadata
-from breadbox.crud.access_control import PUBLIC_GROUP_ID
-from tests import factories
+def test_dataset_with_expiry(
+    client: TestClient, minimal_db: SessionWithUser, mock_celery, settings, monkeypatch
+):
+    user = settings.admin_users[0]
+    headers = {"X-Forwarded-User": user}
+    one_day_in_seconds = 60 * 60 * 24
+
+    file = factories.continuous_matrix_csv_file()
+
+    factories.feature_type(minimal_db, minimal_db.user, "feature_name")
+    factories.sample_type(minimal_db, minimal_db.user, "sample_name")
+
+    file_ids, expected_md5 = upload_and_get_file_ids(client, file)
+
+    def override_time(m, mock_now):
+        m.setattr(dataset_crud, "get_current_datetime", lambda: mock_now)
+        m.setattr(dataset_service, "get_current_datetime", lambda: mock_now)
+
+    with monkeypatch.context() as m:
+        override_time(m, datetime(year=2025, month=1, day=1))
+        response = client.post(
+            "/dataset-v2/",
+            json={
+                "format": "matrix",
+                "name": "a dataset",
+                "units": "a unit",
+                "feature_type": "feature_name",
+                "sample_type": "sample_name",
+                "data_type": "User upload",
+                "file_ids": file_ids,
+                "dataset_md5": expected_md5,
+                "is_transient": False,
+                "expiry_in_seconds": one_day_in_seconds,
+                "group_id": TRANSIENT_GROUP_ID,
+                "value_type": "continuous",
+                "allowed_values": None,
+            },
+            headers=headers,
+        )
+
+        # verify we can't specify expiry on a non-transient dataset
+        assert_status_not_ok(response)
+
+        # try again with transient = True
+        response = client.post(
+            "/dataset-v2/",
+            json={
+                "format": "matrix",
+                "name": "a dataset",
+                "units": "a unit",
+                "feature_type": "feature_name",
+                "sample_type": "sample_name",
+                "data_type": "User upload",
+                "file_ids": file_ids,
+                "dataset_md5": expected_md5,
+                "is_transient": True,
+                "expiry_in_seconds": one_day_in_seconds,
+                "group_id": TRANSIENT_GROUP_ID,
+                "value_type": "continuous",
+                "allowed_values": None,
+            },
+            headers=headers,
+        )
+
+    # now this should work and we should see the expiry having been set
+    assert_status_ok(response)
+    dataset_id = response.json()["result"]["datasetId"]
+    dataset = minimal_db.query(Dataset).filter(Dataset.id == dataset_id).one()
+    assert dataset.expiry == datetime(year=2025, month=1, day=2)
+
+    # now let's try a few dates to make sure we recognize when this is expired
+    # first, make sure that nothing is found before the expiration date
+    with monkeypatch.context() as m:
+        override_time(m, datetime(year=2025, month=1, day=1, hour=1))
+        expired = dataset_crud.find_expired_datasets(minimal_db, timedelta(days=1000))
+        assert len(expired) == 0
+
+    # now make sure that we honor max_age when looking for expired data
+    with monkeypatch.context() as m:
+        override_time(m, datetime(year=2025, month=1, day=1, hour=1))
+        expired = dataset_crud.find_expired_datasets(minimal_db, timedelta(minutes=1))
+        assert len(expired) == 1
+
+    # okay, now make sure that we honor the expiration
+    with monkeypatch.context() as m:
+        override_time(m, datetime(year=2025, month=1, day=2, hour=1))
+        expired = dataset_crud.find_expired_datasets(minimal_db, timedelta(days=1000))
+        assert len(expired) == 1
 
 
 def test_end_to_end_with_mismatched_metadata(
diff --git a/breadbox/tests/factories.py b/breadbox/tests/factories.py
index c3f263376..8242b8625 100644
--- a/breadbox/tests/factories.py
+++ b/breadbox/tests/factories.py
@@ -354,6 +354,7 @@ def tabular_dataset(
         taiga_id=taiga_id,
         dataset_metadata=dataset_metadata,
         dataset_md5=None,
+        expiry=None,
     )
 
     assert columns_metadata is not None