diff --git a/slack-api-client/src/main/java/com/slack/api/util/http/ProxyUrlUtil.java b/slack-api-client/src/main/java/com/slack/api/util/http/ProxyUrlUtil.java
index c5be5343a..308c18d6c 100644
--- a/slack-api-client/src/main/java/com/slack/api/util/http/ProxyUrlUtil.java
+++ b/slack-api-client/src/main/java/com/slack/api/util/http/ProxyUrlUtil.java
@@ -34,8 +34,9 @@ public static ProxyUrl parse(String proxyUrl) {
             return null;
         }
         String[] proxyUrlElements = proxyUrl.split("://");
-        String schema = proxyUrlElements[0] + "://";
-        String urlWithoutSchema = proxyUrlElements[1];
+        boolean withSchema = proxyUrlElements.length == 2;
+        String schema = withSchema ? proxyUrlElements[0] + "://" : "http://";
+        String urlWithoutSchema = withSchema ? proxyUrlElements[1] : proxyUrlElements[0];
         String[] urlWithUserAndPasswordIfTwoElements = urlWithoutSchema.split("@");
         if (urlWithUserAndPasswordIfTwoElements.length == 2) {
             String[] userAndPassword = urlWithUserAndPasswordIfTwoElements[0].split(":");
@@ -51,7 +52,7 @@ public static ProxyUrl parse(String proxyUrl) {
                     .port(hostAndPort.length == 2 ? Integer.parseInt(hostAndPort[1].replace("/", "")) : 80)
                     .build();
         } else {
-            String[] hostAndPort = proxyUrl.split("://")[1].split(":");
+            String[] hostAndPort = (withSchema ? proxyUrlElements[1] : proxyUrlElements[0]).split(":");
             return ProxyUrl.builder()
                     .schema(schema)
                     .host(hostAndPort[0])
diff --git a/slack-api-client/src/test/java/test_locally/api/util/http/ProxyUrlUtilTest.java b/slack-api-client/src/test/java/test_locally/api/util/http/ProxyUrlUtilTest.java
index ead1eb425..e3fa51f6d 100644
--- a/slack-api-client/src/test/java/test_locally/api/util/http/ProxyUrlUtilTest.java
+++ b/slack-api-client/src/test/java/test_locally/api/util/http/ProxyUrlUtilTest.java
@@ -51,4 +51,26 @@ public void parse_username_password() {
     public void parse_invalid_format() {
         ProxyUrlUtil.parse("http://foo:bar:baz@localhost:9000");
     }
+
+    @Test
+    public void parse_no_schema() {
+        ProxyUrlUtil.ProxyUrl expected = ProxyUrlUtil.ProxyUrl.builder()
+                .schema("http://")
+                .host("localhost")
+                .port(9000)
+                .build();
+        assertThat(ProxyUrlUtil.parse("localhost:9000"), is(expected));
+    }
+
+    @Test
+    public void parse_username_password_no_schema() {
+        ProxyUrlUtil.ProxyUrl expected = ProxyUrlUtil.ProxyUrl.builder()
+                .schema("http://")
+                .host("localhost")
+                .username("user")
+                .password("password")
+                .port(9000)
+                .build();
+        assertThat(ProxyUrlUtil.parse("user:password@localhost:9000"), is(expected));
+    }
 }