diff --git a/CHANGELOG.md b/CHANGELOG.md
index 979094a4..421e8315 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+
+- Added the ability to set timeout for Opensearch and Elasticsearch clients by setting the environmental variable `ES_TIMEOUT` [#408](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/408)
+
 ## [v6.0.0] - 2025-06-22
 
 ### Added
diff --git a/README.md b/README.md
index 8ab49c4e..4d2cb807 100644
--- a/README.md
+++ b/README.md
@@ -207,26 +207,27 @@ You can customize additional settings in your `.env` file:
 | `ES_PORT`                    | Port for Elasticsearch/OpenSearch.                                                   | `9200` (ES) / `9202` (OS)| Optional                                                                                    |
 | `ES_USE_SSL`                 | Use SSL for connecting to Elasticsearch/OpenSearch.                                  | `false`                  | Optional                                                                                    |
 | `ES_VERIFY_CERTS`            | Verify SSL certificates when connecting.                                             | `false`                  | Optional                                                                                    |
+| `ES_TIMEOUT`                 | Client timeout for Elasticsearch/OpenSearch.                                         | DB client default        | Optional                                                                                    |
 | `STAC_FASTAPI_TITLE`         | Title of the API in the documentation.                                               | `stac-fastapi-<backend>` | Optional                                                                                    |
 | `STAC_FASTAPI_DESCRIPTION`   | Description of the API in the documentation.                                         | N/A                      | Optional                                                                                    |
 | `STAC_FASTAPI_VERSION`       | API version.                                                                         | `2.1`                    | Optional                                                                                    |
-| `STAC_FASTAPI_LANDING_PAGE_ID` | Landing page ID                                                                      | `stac-fastapi`           | Optional                                                                                    |
+| `STAC_FASTAPI_LANDING_PAGE_ID` | Landing page ID                                                                    | `stac-fastapi`           | Optional                                                                                    |
 | `APP_HOST`                   | Server bind address.                                                                 | `0.0.0.0`                | Optional                                                                                    |
 | `APP_PORT`                   | Server port.                                                                         | `8080`                   | Optional                                                                                    |
 | `ENVIRONMENT`                | Runtime environment.                                                                 | `local`                  | Optional                                                                                    |
 | `WEB_CONCURRENCY`            | Number of worker processes.                                                          | `10`                     | Optional                                                                                    |
 | `RELOAD`                     | Enable auto-reload for development.                                                  | `true`                   | Optional                                                                                    |
 | `STAC_FASTAPI_RATE_LIMIT`    | API rate limit per client.                                                           | `200/minute`             | Optional                                                                                    |
-| `BACKEND`                    | Tests-related variable                                                               | `elasticsearch` or `opensearch` based on the backend | Optional                                                                                    |
-| `ELASTICSEARCH_VERSION`          | Version of Elasticsearch to use.                                                         | `8.11.0`                      | Optional                                                                                    |                                                                             |
-| `OPENSEARCH_VERSION`         | OpenSearch version                                                                   | `2.11.1`                 | Optional       
-| `ENABLE_DIRECT_RESPONSE`         | Enable direct response for maximum performance (disables all FastAPI dependencies, including authentication, custom status codes, and validation) | `false`                  | Optional       
-| `RAISE_ON_BULK_ERROR`         | Controls whether bulk insert operations raise exceptions on errors. If set to `true`, the operation will stop and raise an exception when an error occurs. If set to `false`, errors will be logged, and the operation will continue. **Note:** STAC Item and ItemCollection validation errors will always raise, regardless of this flag. | `false`             Optional                                                                                |
-| `DATABASE_REFRESH`              | Controls whether database operations refresh the index immediately after changes. If set to `true`, changes will be immediately searchable. If set to `false`, changes may not be immediately visible but can improve performance for bulk operations. If set to `wait_for`, changes will wait for the next refresh cycle to become visible. | `false`                  | Optional |
+| `BACKEND`                    | Tests-related variable                                                               | `elasticsearch` or `opensearch` based on the backend | Optional                                                        |
+| `ELASTICSEARCH_VERSION`      | Version of Elasticsearch to use.                                                     | `8.11.0`                 | Optional                                                                                    |
+| `OPENSEARCH_VERSION`         | OpenSearch version                                                                   | `2.11.1`                 | Optional                                                                                    |
+| `ENABLE_DIRECT_RESPONSE`     | Enable direct response for maximum performance (disables all FastAPI dependencies, including authentication, custom status codes, and validation) | `false`                  | Optional                       |
+| `RAISE_ON_BULK_ERROR`        | Controls whether bulk insert operations raise exceptions on errors. If set to `true`, the operation will stop and raise an exception when an error occurs. If set to `false`, errors will be logged, and the operation will continue. **Note:** STAC Item and ItemCollection validation errors will always raise, regardless of this flag. | `false` | Optional |
+| `DATABASE_REFRESH`           | Controls whether database operations refresh the index immediately after changes. If set to `true`, changes will be immediately searchable. If set to `false`, changes may not be immediately visible but can improve performance for bulk operations. If set to `wait_for`, changes will wait for the next refresh cycle to become visible. | `false` | Optional |
 | `ENABLE_TRANSACTIONS_EXTENSIONS` | Enables or disables the Transactions and Bulk Transactions API extensions. If set to `false`, the POST `/collections` route and related transaction endpoints (including bulk transaction operations) will be unavailable in the API. This is useful for deployments where mutating the catalog via the API should be prevented. | `true` | Optional |
 
 > [!NOTE]
-> The variables `ES_HOST`, `ES_PORT`, `ES_USE_SSL`, and `ES_VERIFY_CERTS` apply to both Elasticsearch and OpenSearch backends, so there is no need to rename the key names to `OS_` even if you're using OpenSearch.
+> The variables `ES_HOST`, `ES_PORT`, `ES_USE_SSL`, `ES_VERIFY_CERTS` and `ES_TIMEOUT` apply to both Elasticsearch and OpenSearch backends, so there is no need to rename the key names to `OS_` even if you're using OpenSearch.
 
 ## Interacting with the API
 
diff --git a/stac_fastapi/elasticsearch/stac_fastapi/elasticsearch/config.py b/stac_fastapi/elasticsearch/stac_fastapi/elasticsearch/config.py
index 49495854..c5b6e3dd 100644
--- a/stac_fastapi/elasticsearch/stac_fastapi/elasticsearch/config.py
+++ b/stac_fastapi/elasticsearch/stac_fastapi/elasticsearch/config.py
@@ -56,6 +56,10 @@ def _es_config() -> Dict[str, Any]:
     if (u := os.getenv("ES_USER")) and (p := os.getenv("ES_PASS")):
         config["http_auth"] = (u, p)
 
+    # Include timeout setting if set
+    if request_timeout := os.getenv("ES_TIMEOUT"):
+        config["request_timeout"] = request_timeout
+
     # Explicitly exclude SSL settings when not using SSL
     if not use_ssl:
         return config
diff --git a/stac_fastapi/opensearch/stac_fastapi/opensearch/config.py b/stac_fastapi/opensearch/stac_fastapi/opensearch/config.py
index 3fe4d71b..08e9a42a 100644
--- a/stac_fastapi/opensearch/stac_fastapi/opensearch/config.py
+++ b/stac_fastapi/opensearch/stac_fastapi/opensearch/config.py
@@ -53,6 +53,10 @@ def _es_config() -> Dict[str, Any]:
 
         config["headers"] = headers
 
+    # Include timeout setting if set
+    if timeout := os.getenv("ES_TIMEOUT"):
+        config["timeout"] = timeout
+
     # Explicitly exclude SSL settings when not using SSL
     if not use_ssl:
         return config

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