diff --git a/backend/remote-state/azure/backend.go b/backend/remote-state/azure/backend.go
index a2135c44196a..ebb5247e922f 100644
--- a/backend/remote-state/azure/backend.go
+++ b/backend/remote-state/azure/backend.go
@@ -16,18 +16,21 @@ func New() backend.Backend {
 				Type:        schema.TypeString,
 				Required:    true,
 				Description: "The name of the storage account.",
+				DefaultFunc: schema.EnvDefaultFunc("ARM_STORAGE_ACCOUNT_NAME", nil),
 			},
 
 			"container_name": {
 				Type:        schema.TypeString,
 				Required:    true,
 				Description: "The container name.",
+				DefaultFunc: schema.EnvDefaultFunc("ARM_STORAGE_CONTAINER_NAME", nil),
 			},
 
 			"key": {
 				Type:        schema.TypeString,
 				Required:    true,
 				Description: "The blob key.",
+				DefaultFunc: schema.EnvDefaultFunc("ARM_STORAGE_BLOB_KEY", nil),
 			},
 
 			"environment": {
diff --git a/backend/remote-state/s3/backend.go b/backend/remote-state/s3/backend.go
index ae9bf1fbc9b2..2bf1d97a102e 100644
--- a/backend/remote-state/s3/backend.go
+++ b/backend/remote-state/s3/backend.go
@@ -21,12 +21,14 @@ func New() backend.Backend {
 				Type:        schema.TypeString,
 				Required:    true,
 				Description: "The name of the S3 bucket",
+				DefaultFunc: schema.EnvDefaultFunc("AWS_S3_BUCKET", nil),
 			},
 
 			"key": {
 				Type:        schema.TypeString,
 				Required:    true,
 				Description: "The path to the state file inside the bucket",
+				DefaultFunc: schema.EnvDefaultFunc("AWS_S3_KEY", nil),
 				ValidateFunc: func(v interface{}, s string) ([]string, []error) {
 					// s3 will strip leading slashes from an object, so while this will
 					// technically be accepted by s3, it will break our workspace hierarchy.
diff --git a/website/docs/backends/types/azurerm.html.md b/website/docs/backends/types/azurerm.html.md
index 76caa26b7a5c..48bc8724cd1c 100644
--- a/website/docs/backends/types/azurerm.html.md
+++ b/website/docs/backends/types/azurerm.html.md
@@ -145,11 +145,11 @@ data "terraform_remote_state" "foo" {
 
 The following configuration options are supported:
 
-* `storage_account_name` - (Required) The Name of [the Storage Account](https://www.terraform.io/docs/providers/azurerm/r/storage_account.html).
+* `storage_account_name` - (Required) The Name of [the Storage Account](https://www.terraform.io/docs/providers/azurerm/r/storage_account.html). This can also be sourced from the `ARM_STORAGE_ACCOUNT_NAME` environment variable.
 
-* `container_name` - (Required) The Name of [the Storage Container](https://www.terraform.io/docs/providers/azurerm/r/storage_container.html) within the Storage Account.
+* `container_name` - (Required) The Name of [the Storage Container](https://www.terraform.io/docs/providers/azurerm/r/storage_container.html) within the Storage Account. This can also be sourced from the `ARM_STORAGE_CONTAINER_NAME` environment variable.
 
-* `key` - (Required) The name of the Blob used to retrieve/store Terraform's State file inside the Storage Container.
+* `key` - (Required) The name of the Blob used to retrieve/store Terraform's State file inside the Storage Container. When using workspaces, the workspace state blob key will be prefixed with this value. This can also be sourced from the `ARM_STORAGE_BLOB_KEY` environment variable.
 
 * `environment` - (Optional) The Azure Environment which should be used. This can also be sourced from the `ARM_ENVIRONMENT` environment variable. Possible values are `public`, `china`, `german`, `stack` and `usgovernment`. Defaults to `public`.
 
diff --git a/website/docs/backends/types/s3.html.md b/website/docs/backends/types/s3.html.md
index 5868b10f9aec..4e7a06407d40 100644
--- a/website/docs/backends/types/s3.html.md
+++ b/website/docs/backends/types/s3.html.md
@@ -136,8 +136,8 @@ data.terraform_remote_state.network:
 
 The following configuration options or environment variables are supported:
 
- * `bucket` - (Required) The name of the S3 bucket.
- * `key` - (Required) The path to the state file inside the bucket. When using
+ * `bucket` / `AWS_S3_BUCKET` - (Required) The name of the S3 bucket.
+ * `key` / `AWS_S3_KEY` - (Required) The path to the state file inside the bucket. When using
    a non-default [workspace](/docs/state/workspaces.html), the state path will
    be `/workspace_key_prefix/workspace_name/key`
  * `region` / `AWS_DEFAULT_REGION` - (Optional) The region of the S3
@@ -163,8 +163,7 @@ The following configuration options or environment variables are supported:
  * `shared_credentials_file`  - (Optional) This is the path to the
    shared credentials file. If this is not set and a profile is specified,
    `~/.aws/credentials` will be used.
- * `token` - (Optional) Use this to set an MFA token. It can also be
-   sourced from the `AWS_SESSION_TOKEN` environment variable.
+ * `token` / `AWS_SESSION_TOKEN` - (Optional) Use this to set an MFA token.
  * `role_arn` - (Optional) The role to be assumed.
  * `assume_role_policy` - (Optional) The permissions applied when assuming a role.
  * `external_id` - (Optional) The external ID to use when assuming the role.