diff --git a/docs/cli.md b/docs/cli.md
index 69476c852b5..65f085a814b 100644
--- a/docs/cli.md
+++ b/docs/cli.md
@@ -190,11 +190,13 @@ poetry install --only dev
 ```
 
 You can also specify the extras you want installed
-by passing the `-E|--extras` option (See [Extras]({{< relref "pyproject#extras" >}}) for more info)
+by passing the `-E|--extras` option (See [Extras]({{< relref "pyproject#extras" >}}) for more info).
+Pass `--all-extras` to install all defined extras for a project.
 
 ```bash
 poetry install --extras "mysql pgsql"
 poetry install -E mysql -E pgsql
+poetry install --all-extras
 ```
 
 By default `poetry` will install your project's package every time you run `install`:
@@ -227,6 +229,7 @@ option is used.
 * `--no-root`: Do not install the root package (your project).
 * `--dry-run`: Output the operations but do not execute anything (implicitly enables --verbose).
 * `--extras (-E)`: Features to install (multiple values allowed).
+* `--all-extras`: Install all extra features (conflicts with --extras).
 * `--no-dev`: Do not install dev dependencies. (**Deprecated**)
 * `--dev-only`: Only install dev dependencies. (**Deprecated**)
 * `--remove-untracked`: Remove dependencies not presented in the lock file. (**Deprecated**)
diff --git a/docs/pyproject.md b/docs/pyproject.md
index 7c5cc90d3af..e1d526aea02 100644
--- a/docs/pyproject.md
+++ b/docs/pyproject.md
@@ -384,6 +384,12 @@ poetry install --extras "mysql pgsql"
 poetry install -E mysql -E pgsql
 ```
 
+Or, you can install all extras with the `--all-extras` option:
+
+```bash
+poetry install --all-extras
+```
+
 When installing or specifying Poetry-built packages, the extras defined in this section can be activated
 as described in [PEP 508](https://www.python.org/dev/peps/pep-0508/#extras).
 
diff --git a/src/poetry/console/commands/install.py b/src/poetry/console/commands/install.py
index a7389bf28b8..e2776d4e004 100644
--- a/src/poetry/console/commands/install.py
+++ b/src/poetry/console/commands/install.py
@@ -52,6 +52,7 @@ class InstallCommand(InstallerCommand):
             flag=False,
             multiple=True,
         ),
+        option("all-extras", None, "Install all extra dependencies."),
     ]
 
     help = """The <info>install</info> command reads the <comment>poetry.lock</> file from
@@ -79,12 +80,23 @@ def handle(self) -> int:
             self.poetry.config.get("experimental.new-installer", False)
         )
 
-        extras = []
-        for extra in self.option("extras", []):
-            if " " in extra:
-                extras += [e.strip() for e in extra.split(" ")]
-            else:
-                extras.append(extra)
+        if self.option("extras") and self.option("all-extras"):
+            self.line_error(
+                "<error>You cannot specify explicit"
+                " `<fg=yellow;options=bold>--extras</>` while installing"
+                " using `<fg=yellow;options=bold>--all-extras</>`.</error>"
+            )
+            return 1
+
+        if self.option("all-extras"):
+            extras = list(self.poetry.package.extras.keys())
+        else:
+            extras = []
+            for extra in self.option("extras", []):
+                if " " in extra:
+                    extras += [e.strip() for e in extra.split(" ")]
+                else:
+                    extras.append(extra)
 
         self._installer.extras(extras)
 
diff --git a/tests/console/commands/test_install.py b/tests/console/commands/test_install.py
index 027b3de2f92..2be8a4a5e3c 100644
--- a/tests/console/commands/test_install.py
+++ b/tests/console/commands/test_install.py
@@ -30,6 +30,8 @@
 
 [tool.poetry.dependencies]
 python = "~2.7 || ^3.4"
+fizz = { version = "^1.0", optional = true }
+buzz = { version = "^2.0", optional = true }
 
 [tool.poetry.group.foo.dependencies]
 foo = "^1.0"
@@ -48,6 +50,10 @@
 
 [tool.poetry.group.bam.dependencies]
 bam = "^1.4"
+
+[tool.poetry.extras]
+extras_a = [ "fizz" ]
+extras_b = [ "buzz" ]
 """
 
 
@@ -132,3 +138,43 @@ def test_sync_option_is_passed_to_the_installer(
     tester.execute("--sync")
 
     assert tester.command.installer._requires_synchronization
+
+
+def test_no_all_extras_doesnt_populate_installer(
+    tester: CommandTester, mocker: MockerFixture
+):
+    """
+    Not passing --all-extras means the installer doesn't see any extras.
+    """
+    mocker.patch.object(tester.command.installer, "run", return_value=1)
+
+    tester.execute()
+
+    assert not tester.command.installer._extras
+
+
+def test_all_extras_populates_installer(tester: CommandTester, mocker: MockerFixture):
+    """
+    The --all-extras option results in extras passed to the installer.
+    """
+    mocker.patch.object(tester.command.installer, "run", return_value=1)
+
+    tester.execute("--all-extras")
+
+    assert tester.command.installer._extras == ["extras_a", "extras_b"]
+
+
+def test_extras_conlicts_all_extras(tester: CommandTester, mocker: MockerFixture):
+    """
+    The --extras doesn't make sense with --all-extras.
+    """
+    mocker.patch.object(tester.command.installer, "run", return_value=0)
+
+    tester.execute("--extras foo --all-extras")
+
+    assert tester.status_code == 1
+    assert (
+        tester.io.fetch_error()
+        == "You cannot specify explicit `--extras` while installing using"
+        " `--all-extras`.\n"
+    )