diff --git a/Octokit.Reactive/Clients/IObservableIssuesClient.cs b/Octokit.Reactive/Clients/IObservableIssuesClient.cs
index 008d9955b0..cae13e02a1 100644
--- a/Octokit.Reactive/Clients/IObservableIssuesClient.cs
+++ b/Octokit.Reactive/Clients/IObservableIssuesClient.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Reactive;
 
 namespace Octokit.Reactive
 {
@@ -156,5 +157,25 @@ public interface IObservableIssuesClient
         /// </param>
         /// <returns></returns>
         IObservable<Issue> Update(string owner, string name, int number, IssueUpdate issueUpdate);
+        
+         /// <summary>
+         /// Locks an issue for the specified repository. Issue owners and users with push access can lock an issue.
+         /// </summary>
+         /// <remarks>https://developer.github.com/v3/issues/#lock-an-issue</remarks>
+         /// <param name="owner">The owner of the repository</param>
+         /// <param name="name">The name of the repository</param>
+         /// <param name="number">The issue number</param>
+         /// <returns></returns>
+         IObservable<Unit> LockIssue(string owner, string name, int number);
+ 
+         /// <summary>
+         /// Unlocks an issue for the specified repository. Issue owners and users with push access can unlock an issue.
+         /// </summary>
+         /// <remarks>https://developer.github.com/v3/issues/#unlock-an-issue</remarks>
+         /// <param name="owner">The owner of the repository</param>
+         /// <param name="name">The name of the repository</param>
+         /// <param name="number">The issue number</param>
+         /// <returns></returns>
+         IObservable<Unit> UnlockIssue(string owner, string name, int number);
     }
-}
+}
\ No newline at end of file
diff --git a/Octokit.Reactive/Clients/ObservableIssuesClient.cs b/Octokit.Reactive/Clients/ObservableIssuesClient.cs
index 4571696334..47d2b9f07b 100644
--- a/Octokit.Reactive/Clients/ObservableIssuesClient.cs
+++ b/Octokit.Reactive/Clients/ObservableIssuesClient.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Reactive.Threading.Tasks;
 using Octokit.Reactive.Internal;
+using System.Reactive;
 
 namespace Octokit.Reactive
 {
@@ -222,5 +223,37 @@ public IObservable<Issue> Update(string owner, string name, int number, IssueUpd
 
             return _client.Update(owner, name, number, issueUpdate).ToObservable();
         }
+        
+         /// <summary>
+         /// Locks an issue for the specified repository. Issue owners and users with push access can lock an issue.
+         /// </summary>
+         /// <remarks>https://developer.github.com/v3/issues/#lock-an-issue</remarks>
+         /// <param name="owner">The owner of the repository</param>
+         /// <param name="name">The name of the repository</param>
+         /// <param name="number">The issue number</param>
+         /// <returns></returns>
+         public IObservable<Unit> LockIssue(string owner, string name, int number)
+         {
+             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+             Ensure.ArgumentNotNullOrEmptyString(name, "name");
+ 
+             return _client.LockIssue(owner, name, number).ToObservable();
+         }
+ 
+         /// <summary>
+         /// Unlocks an issue for the specified repository. Issue owners and users with push access can unlock an issue.
+         /// </summary>
+         /// <remarks>https://developer.github.com/v3/issues/#unlock-an-issue</remarks>
+         /// <param name="owner">The owner of the repository</param>
+         /// <param name="name">The name of the repository</param>
+         /// <param name="number">The issue number</param>
+         /// <returns></returns>
+         public IObservable<Unit> UnlockIssue(string owner, string name, int number)
+         {
+             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+             Ensure.ArgumentNotNullOrEmptyString(name, "name");
+ 
+             return _client.UnlockIssue(owner, name, number).ToObservable();
+         }
     }
 }
diff --git a/Octokit.Tests.Integration/Clients/IssuesClientTests.cs b/Octokit.Tests.Integration/Clients/IssuesClientTests.cs
index 73284093a5..fec271d0bf 100644
--- a/Octokit.Tests.Integration/Clients/IssuesClientTests.cs
+++ b/Octokit.Tests.Integration/Clients/IssuesClientTests.cs
@@ -62,6 +62,26 @@ public async Task CanCreateRetrieveAndCloseIssue()
     }
 
     [IntegrationTest]
+    public async Task CanLockAndUnlockIssue()
+    {
+         var newIssue = new NewIssue("a test issue") { Body = "A new unassigned issue" };
+         var issue = await _issuesClient.Create(_context.RepositoryOwner, _context.RepositoryName, newIssue);
+         var retrieved = await _issuesClient.Get(_context.RepositoryOwner, _context.RepositoryName, issue.Number);
+ 
+         Assert.Equal(false, issue.Locked);
+ 
+         await _issuesClient.LockIssue(_context.RepositoryOwner, _context.RepositoryName, issue.Number);
+         retrieved = await _issuesClient.Get(_context.RepositoryOwner, _context.RepositoryName, issue.Number);
+         Assert.NotNull(retrieved);
+         Assert.Equal(true, issue.Locked);
+ 
+         await _issuesClient.UnlockIssue(_context.RepositoryOwner, _context.RepositoryName, issue.Number);
+         retrieved = await _issuesClient.Get(_context.RepositoryOwner, _context.RepositoryName, issue.Number);
+         Assert.NotNull(retrieved);
+         Assert.Equal(false, issue.Locked);
+     }
+ 
+     [IntegrationTest]
     public async Task CanListOpenIssuesWithDefaultSort()
     {
         var newIssue1 = new NewIssue("A test issue1") { Body = "A new unassigned issue" };
diff --git a/Octokit.Tests.Integration/Reactive/ObservableIssuesClientTests.cs b/Octokit.Tests.Integration/Reactive/ObservableIssuesClientTests.cs
index 5eb94af756..1b40a7ac92 100644
--- a/Octokit.Tests.Integration/Reactive/ObservableIssuesClientTests.cs
+++ b/Octokit.Tests.Integration/Reactive/ObservableIssuesClientTests.cs
@@ -72,6 +72,23 @@ public async Task CanCreateAndUpdateIssues()
         Assert.Equal("Modified integration test issue", updateResult.Title);
     }
 
+     [IntegrationTest]
+     public async Task CanLockAndUnlockIssues()
+     {
+         var newIssue = new NewIssue("Integration Test Issue");
+ 
+         var createResult = await _client.Create(_context.RepositoryOwner, _context.RepositoryName, newIssue);
+         Assert.Equal(false, createResult.Locked);
+ 
+         await _client.LockIssue(_context.RepositoryOwner, _context.RepositoryName, createResult.Number);
+         var lockResult = await _client.Get(_context.RepositoryOwner, _context.RepositoryName, createResult.Number);
+         Assert.Equal(true, lockResult.Locked);
+ 
+         await _client.UnlockIssue(_context.RepositoryOwner, _context.RepositoryName, createResult.Number);
+         var unlockIssueResult = await _client.Get(_context.RepositoryOwner, _context.RepositoryName, createResult.Number);
+         Assert.Equal(false, unlockIssueResult.Locked);
+    }
+ 
     public void Dispose()
     {
         _context.Dispose();
diff --git a/Octokit.Tests/Clients/IssuesClientTests.cs b/Octokit.Tests/Clients/IssuesClientTests.cs
index 2f3b759b19..f4086d6833 100644
--- a/Octokit.Tests/Clients/IssuesClientTests.cs
+++ b/Octokit.Tests/Clients/IssuesClientTests.cs
@@ -185,6 +185,58 @@ public async Task EnsuresArgumentsNotNull()
             }
         }
 
+        public class TheLockIssueMethod
+        {
+            [Fact]
+            public void PostsToCorrectUrl()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new IssuesClient(connection);
+
+                client.LockIssue("fake", "repo", 42);
+
+                connection.Received().Put(Arg.Is<Uri>(u => u.ToString() == "repos/fake/repo/issues/42/lock"));
+            }
+
+            [Fact]
+            public async Task EnsuresArgumentsNotNull()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new IssuesClient(connection);
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.LockIssue(null, "name", 1));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.LockIssue("", "name", 1));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.LockIssue("owner", null, 1));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.LockIssue("owner", "", 1));
+            }
+        }
+
+        public class TheUnlockIssueMethod
+        {
+            [Fact]
+            public void PostsToCorrectUrl()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new IssuesClient(connection);
+
+                client.UnlockIssue("fake", "repo", 42);
+
+                connection.Received().Delete(Arg.Is<Uri>(u => u.ToString() == "repos/fake/repo/issues/42/lock"));
+            }
+
+            [Fact]
+            public async Task EnsuresArgumentsNotNull()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new IssuesClient(connection);
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.UnlockIssue(null, "name", 1));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.UnlockIssue("", "name", 1));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.UnlockIssue("owner", null, 1));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.UnlockIssue("owner", "", 1));
+            }
+        }
+
         public class TheCtor
         {
             [Fact]
diff --git a/Octokit.Tests/Reactive/ObservableIssuesClientTests.cs b/Octokit.Tests/Reactive/ObservableIssuesClientTests.cs
index aa23f958fd..61afa771cd 100644
--- a/Octokit.Tests/Reactive/ObservableIssuesClientTests.cs
+++ b/Octokit.Tests/Reactive/ObservableIssuesClientTests.cs
@@ -329,11 +329,61 @@ public void EnsuresArgumentsNotNull()
             var gitHubClient = Substitute.For<IGitHubClient>();
             var client = new ObservableIssuesClient(gitHubClient);
 
-            Assert.Throws<ArgumentNullException>(() => client.Create(null, "name", new NewIssue("title")));
-            Assert.Throws<ArgumentException>(() => client.Create("", "name", new NewIssue("x")));
-            Assert.Throws<ArgumentNullException>(() => client.Create("owner", null, new NewIssue("x")));
-            Assert.Throws<ArgumentException>(() => client.Create("owner", "", new NewIssue("x")));
-            Assert.Throws<ArgumentNullException>(() => client.Create("owner", "name", null));
+            Assert.Throws<ArgumentNullException>(() => client.Update(null, "name", 42, new IssueUpdate()));
+            Assert.Throws<ArgumentException>(() => client.Update("", "name", 42, new IssueUpdate()));
+            Assert.Throws<ArgumentNullException>(() => client.Update("owner", null, 42, new IssueUpdate()));
+            Assert.Throws<ArgumentException>(() => client.Update("owner", "", 42, new IssueUpdate()));
+            Assert.Throws<ArgumentNullException>(() => client.Update("owner", "name", 42, null));
+        }
+    }
+
+    public class TheLockIssueMethod
+    {
+        [Fact]
+        public void LockIssue()
+        {
+            var gitHubClient = Substitute.For<IGitHubClient>();
+            var client = new ObservableIssuesClient(gitHubClient);
+
+            client.LockIssue("fake", "repo", 42);
+            gitHubClient.Issue.Received().LockIssue("fake", "repo", 42);
+        }
+
+        [Fact]
+        public void EnsuresArgumentsNotNull()
+        {
+            var gitHubClient = Substitute.For<IGitHubClient>();
+            var client = new ObservableIssuesClient(gitHubClient);
+
+            Assert.Throws<ArgumentNullException>(() => client.LockIssue(null, "name", 42));
+            Assert.Throws<ArgumentException>(() => client.LockIssue("", "name", 42));
+            Assert.Throws<ArgumentNullException>(() => client.LockIssue("owner", null, 42));
+            Assert.Throws<ArgumentException>(() => client.LockIssue("owner", "", 42));
+        }
+    }
+
+    public class TheUnlockIssueMethod
+    {
+        [Fact]
+        public void UnlockIssue()
+        {
+            var gitHubClient = Substitute.For<IGitHubClient>();
+            var client = new ObservableIssuesClient(gitHubClient);
+
+            client.UnlockIssue("fake", "repo", 42);
+            gitHubClient.Issue.Received().UnlockIssue("fake", "repo", 42);
+        }
+
+        [Fact]
+        public void EnsuresArgumentsNotNull()
+        {
+            var gitHubClient = Substitute.For<IGitHubClient>();
+            var client = new ObservableIssuesClient(gitHubClient);
+
+            Assert.Throws<ArgumentNullException>(() => client.UnlockIssue(null, "name", 42));
+            Assert.Throws<ArgumentException>(() => client.UnlockIssue("", "name", 42));
+            Assert.Throws<ArgumentNullException>(() => client.UnlockIssue("owner", null, 42));
+            Assert.Throws<ArgumentException>(() => client.UnlockIssue("owner", "", 42));
         }
     }
 
diff --git a/Octokit/Clients/IIssuesClient.cs b/Octokit/Clients/IIssuesClient.cs
index bc0e362cb9..f6f61dea4a 100644
--- a/Octokit/Clients/IIssuesClient.cs
+++ b/Octokit/Clients/IIssuesClient.cs
@@ -152,10 +152,10 @@ public interface IIssuesClient
         Task<Issue> Create(string owner, string name, NewIssue newIssue);
 
         /// <summary>
-        /// Creates an issue for the specified repository. Any user with pull access to a repository can create an
+        /// Updates an issue for the specified repository. Any user with pull access to a repository can update an
         /// issue.
         /// </summary>
-        /// <remarks>http://developer.github.com/v3/issues/#create-an-issue</remarks>
+        /// <remarks>http://developer.github.com/v3/issues/#edit-an-issue</remarks>
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="number">The issue number</param>
@@ -163,5 +163,25 @@ public interface IIssuesClient
         /// </param>
         /// <returns></returns>
         Task<Issue> Update(string owner, string name, int number, IssueUpdate issueUpdate);
+
+        /// <summary>
+        /// Locks an issue for the specified repository. Issue owners and users with push access can lock an issue.
+        /// </summary>
+        /// <remarks>https://developer.github.com/v3/issues/#lock-an-issue</remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="number">The issue number</param>
+        /// <returns></returns>
+        Task LockIssue(string owner, string name, int number);
+
+        /// <summary>
+        /// Unlocks an issue for the specified repository. Issue owners and users with push access can unlock an issue.
+        /// </summary>
+        /// <remarks>https://developer.github.com/v3/issues/#unlock-an-issue</remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="number">The issue number</param>
+        /// <returns></returns>
+        Task UnlockIssue(string owner, string name, int number);
     }
 }
diff --git a/Octokit/Clients/IssuesClient.cs b/Octokit/Clients/IssuesClient.cs
index 8b924245bb..be4a9641b6 100644
--- a/Octokit/Clients/IssuesClient.cs
+++ b/Octokit/Clients/IssuesClient.cs
@@ -225,5 +225,37 @@ public Task<Issue> Update(string owner, string name, int number, IssueUpdate iss
 
             return ApiConnection.Patch<Issue>(ApiUrls.Issue(owner, name, number), issueUpdate);
         }
+
+        /// <summary>
+        /// Locks an issue for the specified repository. Issue owners and users with push access can lock an issue.
+        /// </summary>
+        /// <remarks>https://developer.github.com/v3/issues/#lock-an-issue</remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="number">The issue number</param>
+        /// <returns></returns>
+        public Task LockIssue(string owner, string name, int number)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+            Ensure.ArgumentNotNullOrEmptyString(name, "name");
+
+            return ApiConnection.Put(ApiUrls.IssueLock(owner, name, number));
+        }
+
+        /// <summary>
+        /// Unlocks an issue for the specified repository. Issue owners and users with push access can unlock an issue.
+        /// </summary>
+        /// <remarks>https://developer.github.com/v3/issues/#unlock-an-issue</remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="number">The issue number</param>
+        /// <returns></returns>
+        public Task UnlockIssue(string owner, string name, int number)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+            Ensure.ArgumentNotNullOrEmptyString(name, "name");
+
+            return ApiConnection.Delete(ApiUrls.IssueLock(owner, name, number));
+        }
     }
 }
diff --git a/Octokit/Helpers/ApiUrls.cs b/Octokit/Helpers/ApiUrls.cs
index bb34ce4624..73e99aa3bc 100644
--- a/Octokit/Helpers/ApiUrls.cs
+++ b/Octokit/Helpers/ApiUrls.cs
@@ -294,6 +294,18 @@ public static Uri Issue(string owner, string name, int number)
             return "repos/{0}/{1}/issues/{2}".FormatUri(owner, name, number);
         }
 
+        /// <summary>
+        /// Returns the <see cref="Uri"/> for the specified issue to be locked/unlocked.
+        /// </summary>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="number">The issue number</param>
+        /// <returns></returns>
+        public static Uri IssueLock(string owner, string name, int number)
+        {
+            return "repos/{0}/{1}/issues/{2}/lock".FormatUri(owner, name, number);
+        }
+
         /// <summary>
         /// Returns the <see cref="Uri"/> for the comments for all issues in a specific repo.
         /// </summary>