diff --git a/homeassistant/components/cast/helpers.py b/homeassistant/components/cast/helpers.py
index dd98a2bc051..dfeb9fce25b 100644
--- a/homeassistant/components/cast/helpers.py
+++ b/homeassistant/components/cast/helpers.py
@@ -237,12 +237,14 @@ def _is_url(url):
     return all([result.scheme, result.netloc])
 
 
-async def _fetch_playlist(hass, url):
+async def _fetch_playlist(hass, url, supported_content_types):
     """Fetch a playlist from the given url."""
     try:
         session = aiohttp_client.async_get_clientsession(hass, verify_ssl=False)
         async with session.get(url, timeout=5) as resp:
             charset = resp.charset or "utf-8"
+            if resp.content_type in supported_content_types:
+                raise PlaylistSupported
             try:
                 playlist_data = (await resp.content.read(64 * 1024)).decode(charset)
             except ValueError as err:
@@ -260,7 +262,16 @@ async def parse_m3u(hass, url):
 
     Based on https://github.com/dvndrsn/M3uParser/blob/master/m3uparser.py
     """
-    m3u_data = await _fetch_playlist(hass, url)
+    # From Mozilla gecko source: https://github.com/mozilla/gecko-dev/blob/c4c1adbae87bf2d128c39832d72498550ee1b4b8/dom/media/DecoderTraits.cpp#L47-L52
+    hls_content_types = (
+        # https://tools.ietf.org/html/draft-pantos-http-live-streaming-19#section-10
+        "application/vnd.apple.mpegurl",
+        # Some sites serve these as the informal HLS m3u type.
+        "application/x-mpegurl",
+        "audio/mpegurl",
+        "audio/x-mpegurl",
+    )
+    m3u_data = await _fetch_playlist(hass, url, hls_content_types)
     m3u_lines = m3u_data.splitlines()
 
     playlist = []
@@ -301,7 +312,7 @@ async def parse_pls(hass, url):
 
     Based on https://github.com/mariob/plsparser/blob/master/src/plsparser.py
     """
-    pls_data = await _fetch_playlist(hass, url)
+    pls_data = await _fetch_playlist(hass, url, ())
 
     pls_parser = configparser.ConfigParser()
     try:
diff --git a/tests/components/cast/test_helpers.py b/tests/components/cast/test_helpers.py
index 0d7a3b1ff14..d729d36a225 100644
--- a/tests/components/cast/test_helpers.py
+++ b/tests/components/cast/test_helpers.py
@@ -14,10 +14,25 @@ from homeassistant.components.cast.helpers import (
 from tests.common import load_fixture
 
 
-async def test_hls_playlist_supported(hass, aioclient_mock):
+@pytest.mark.parametrize(
+    "url,fixture,content_type",
+    (
+        (
+            "http://a.files.bbci.co.uk/media/live/manifesto/audio/simulcast/hls/nonuk/sbr_low/ak/bbc_radio_fourfm.m3u8",
+            "bbc_radio_fourfm.m3u8",
+            None,
+        ),
+        (
+            "https://rthkaudio2-lh.akamaihd.net/i/radio2_1@355865/master.m3u8",
+            "rthkaudio2.m3u8",
+            "application/vnd.apple.mpegurl",
+        ),
+    ),
+)
+async def test_hls_playlist_supported(hass, aioclient_mock, url, fixture, content_type):
     """Test playlist parsing of HLS playlist."""
-    url = "http://a.files.bbci.co.uk/media/live/manifesto/audio/simulcast/hls/nonuk/sbr_low/ak/bbc_radio_fourfm.m3u8"
-    aioclient_mock.get(url, text=load_fixture("bbc_radio_fourfm.m3u8", "cast"))
+    headers = {"content-type": content_type}
+    aioclient_mock.get(url, text=load_fixture(fixture, "cast"), headers=headers)
     with pytest.raises(PlaylistSupported):
         await parse_playlist(hass, url)