diff --git a/Octokit.Reactive/Clients/IObservableRepositoryCommitsClients.cs b/Octokit.Reactive/Clients/IObservableRepositoryCommitsClients.cs
index 927b34c03e..29d4d55ead 100644
--- a/Octokit.Reactive/Clients/IObservableRepositoryCommitsClients.cs
+++ b/Octokit.Reactive/Clients/IObservableRepositoryCommitsClients.cs
@@ -43,5 +43,14 @@ public interface IObservableRepositoryCommitsClient
         /// <param name="request">Used to filter list of commits returned</param>
         /// <returns></returns>
         IObservable<GitHubCommit> GetAll(string owner, string name, CommitRequest request);
+
+        /// <summary>
+        /// Get the SHA-1 of a commit reference
+        /// </summary>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="reference">The repository reference</param>
+        /// <returns></returns>
+        IObservable<string> GetSha1(string owner, string name, string reference);
     }
 }
diff --git a/Octokit.Reactive/Clients/ObservableRepositoryCommitsClients.cs b/Octokit.Reactive/Clients/ObservableRepositoryCommitsClients.cs
index 7982485e39..629142d7dc 100644
--- a/Octokit.Reactive/Clients/ObservableRepositoryCommitsClients.cs
+++ b/Octokit.Reactive/Clients/ObservableRepositoryCommitsClients.cs
@@ -73,5 +73,21 @@ public IObservable<GitHubCommit> GetAll(string owner, string name, CommitRequest
             return _connection.GetAndFlattenAllPages<GitHubCommit>(ApiUrls.RepositoryCommits(owner, name),
                 request.ToParametersDictionary());
         }
+
+        /// <summary>
+        /// Get the SHA-1 of a commit reference
+        /// </summary>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="reference">The repository reference</param>
+        /// <returns></returns>
+        public IObservable<string> GetSha1(string owner, string name, string reference)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+            Ensure.ArgumentNotNullOrEmptyString(name, "name");
+            Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
+
+            return _commit.GetSha1(owner, name, reference).ToObservable();
+        }
     }
 }
diff --git a/Octokit.Tests.Integration/Clients/RepositoryCommitsClientTests.cs b/Octokit.Tests.Integration/Clients/RepositoryCommitsClientTests.cs
index 9546491755..74c4e43e53 100644
--- a/Octokit.Tests.Integration/Clients/RepositoryCommitsClientTests.cs
+++ b/Octokit.Tests.Integration/Clients/RepositoryCommitsClientTests.cs
@@ -87,6 +87,14 @@ public async Task CanGetCommitWithRenamedFiles()
                 .Where(file => file.Status == "renamed")
                 .All(file => string.IsNullOrEmpty(file.PreviousFileName) == false));
         }
+
+        [IntegrationTest]
+        public async Task CanGetSha1()
+        {
+            var sha1 = await _fixture.GetSha1("octokit", "octokit.net", "master");
+
+            Assert.NotNull(sha1);
+        }
     }
 
     public class TestsWithNewRepository : IDisposable
@@ -158,7 +166,17 @@ public async Task CanCompareUsingSha()
             Assert.Equal(0, result.BehindBy);
         }
 
-        async Task CreateTheWorld()
+        [IntegrationTest]
+        public async Task GetSha1FromRepository()
+        {
+            var reference = await CreateTheWorld();
+
+            var sha1 = await _fixture.GetSha1(Helper.UserName, _context.RepositoryName, "master");
+
+            Assert.Equal(reference.Object.Sha, sha1);
+        }
+
+        async Task<Reference> CreateTheWorld()
         {
             var master = await _github.Git.Reference.Get(Helper.UserName, _context.RepositoryName, "heads/master");
 
@@ -174,7 +192,7 @@ async Task CreateTheWorld()
             var newFeature = await CreateCommit("this is the commit to merge into the pull request", featureBranchTree.Sha, newMaster.Sha);
 
             // create branch
-            await _github.Git.Reference.Create(Helper.UserName, _context.RepositoryName, new NewReference("refs/heads/my-branch", newFeature.Sha));
+            return await _github.Git.Reference.Create(Helper.UserName, _context.RepositoryName, new NewReference("refs/heads/my-branch", newFeature.Sha));
         }
 
         async Task<TreeResponse> CreateTree(IDictionary<string, string> treeContents)
diff --git a/Octokit.Tests/Clients/RepositoriesClientTests.cs b/Octokit.Tests/Clients/RepositoriesClientTests.cs
index e74cc97b83..dab4474d7b 100644
--- a/Octokit.Tests/Clients/RepositoriesClientTests.cs
+++ b/Octokit.Tests/Clients/RepositoriesClientTests.cs
@@ -790,5 +790,40 @@ public async Task EnsuresNonNullArguments()
                 await Assert.ThrowsAsync<ArgumentException>(() => client.EditBranch("owner", "repo", "", update));
             }
         }
+
+        public class TheGetSha1Method
+        {
+            [Fact]
+            public void EnsuresNonNullArguments()
+            {
+                var client = new RepositoryCommitsClient(Substitute.For<IApiConnection>());
+
+                Assert.ThrowsAsync<ArgumentException>(() => client.GetSha1("", "name", "reference"));
+                Assert.ThrowsAsync<ArgumentException>(() => client.GetSha1("owner", "", "reference"));
+                Assert.ThrowsAsync<ArgumentException>(() => client.GetSha1("owner", "name", ""));
+            }
+
+            [Fact]
+            public async Task EnsuresNonEmptyArguments()
+            {
+                var client = new RepositoryCommitsClient(Substitute.For<IApiConnection>());
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetSha1(null, "name", "reference"));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetSha1("owner", null, "reference"));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetSha1("owner", "name", null));
+            }
+
+            [Fact]
+            public void GetsCorrectUrl()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new RepositoryCommitsClient(connection);
+
+                client.GetSha1("owner", "name", "reference");
+
+                connection.Received()
+                    .Get<string>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/name/commits/reference"), null, AcceptHeaders.CommitReferenceSha1Preview);
+            }
+        }
     }
 }
diff --git a/Octokit.Tests/Octokit.Tests.csproj b/Octokit.Tests/Octokit.Tests.csproj
index 5c6484c309..9f226d4e3a 100644
--- a/Octokit.Tests/Octokit.Tests.csproj
+++ b/Octokit.Tests/Octokit.Tests.csproj
@@ -212,6 +212,7 @@
     <Compile Include="Reactive\ObservableReleasesClientTests.cs" />
     <Compile Include="Reactive\ObservablePullRequestReviewCommentsClientTests.cs" />
     <Compile Include="Reactive\ObservableRepositoriesClientTests.cs" />
+    <Compile Include="Reactive\ObservableRepositoryCommitsClientTests.cs" />
     <Compile Include="Reactive\ObservableRepositoryDeployKeysClientTests.cs" />
     <Compile Include="Reactive\ObservableGistsTests.cs" />
     <Compile Include="Reactive\ObservableStarredClientTests.cs" />
diff --git a/Octokit.Tests/Reactive/ObservableRepositoryCommitsClientTests.cs b/Octokit.Tests/Reactive/ObservableRepositoryCommitsClientTests.cs
new file mode 100644
index 0000000000..bcd91f377e
--- /dev/null
+++ b/Octokit.Tests/Reactive/ObservableRepositoryCommitsClientTests.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Reactive.Threading.Tasks;
+using System.Threading.Tasks;
+using NSubstitute;
+using Octokit.Reactive;
+using Xunit;
+
+namespace Octokit.Tests.Reactive
+{
+    public class ObservableRepositoryCommitsClientTests
+    {
+        public class TheCtor
+        {
+            [Fact]
+            public void EnsuresArgument()
+            {
+                Assert.Throws<ArgumentNullException>(() => new ObservableRepositoryCommitsClient(null));
+            }
+        }
+
+        public class TheGetSha1Method
+        {
+            [Fact]
+            public void EnsuresNonEmptyArguments()
+            {
+                var client = new ObservableRepositoryCommitsClient(Substitute.For<IGitHubClient>());
+
+                Assert.ThrowsAsync<ArgumentException>(() => client.GetSha1("", "name", "reference").ToTask());
+                Assert.ThrowsAsync<ArgumentException>(() => client.GetSha1("owner", "", "reference").ToTask());
+                Assert.ThrowsAsync<ArgumentException>(() => client.GetSha1("owner", "name", "").ToTask());
+            }
+
+            [Fact]
+            public async Task EnsuresNonNullArguments()
+            {
+                var client = new ObservableRepositoryCommitsClient(Substitute.For<IGitHubClient>());
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetSha1(null, "name", "reference").ToTask());
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetSha1("owner", null, "reference").ToTask());
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetSha1("owner", "name", null).ToTask());
+            }
+
+            [Fact]
+            public void GetsCorrectUrl()
+            {
+                var gitHubClient = Substitute.For<IGitHubClient>();
+                var client = new ObservableRepositoryCommitsClient(gitHubClient);
+
+                client.GetSha1("owner", "name", "reference");
+
+                gitHubClient
+                    .Received()
+                    .Repository
+                    .Commit
+                    .GetSha1("owner", "name", "reference");
+            }
+        }
+    }
+}
diff --git a/Octokit/Clients/IRepositoryCommitsClient.cs b/Octokit/Clients/IRepositoryCommitsClient.cs
index f2b09f2b49..bd48619266 100644
--- a/Octokit/Clients/IRepositoryCommitsClient.cs
+++ b/Octokit/Clients/IRepositoryCommitsClient.cs
@@ -50,5 +50,14 @@ public interface IRepositoryCommitsClient
         /// <param name="request">Used to filter list of commits returned</param>
         /// <returns></returns>
         Task<IReadOnlyList<GitHubCommit>> GetAll(string owner, string name, CommitRequest request);
+
+        /// <summary>
+        /// Get the SHA-1 of a commit reference
+        /// </summary>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="reference">The repository reference</param>
+        /// <returns></returns>
+        Task<string> GetSha1(string owner, string name, string reference);
     }
 }
diff --git a/Octokit/Clients/RepositoryCommitsClient.cs b/Octokit/Clients/RepositoryCommitsClient.cs
index 0e8ad1b26f..e5fa961346 100644
--- a/Octokit/Clients/RepositoryCommitsClient.cs
+++ b/Octokit/Clients/RepositoryCommitsClient.cs
@@ -79,5 +79,21 @@ public Task<IReadOnlyList<GitHubCommit>> GetAll(string owner, string name, Commi
             return _apiConnection.GetAll<GitHubCommit>(ApiUrls.RepositoryCommits(owner, name),
                 request.ToParametersDictionary());
         }
+
+        /// <summary>
+        /// Get the SHA-1 of a commit reference
+        /// </summary>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="reference">The repository reference</param>
+        /// <returns></returns>
+        public Task<string> GetSha1(string owner, string name, string reference)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+            Ensure.ArgumentNotNullOrEmptyString(name, "name");
+            Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
+
+            return _apiConnection.Get<string>(ApiUrls.RepositoryCommit(owner, name, reference), null, AcceptHeaders.CommitReferenceSha1Preview);
+        }
     }
 }
\ No newline at end of file
diff --git a/Octokit/Helpers/AcceptHeaders.cs b/Octokit/Helpers/AcceptHeaders.cs
index d94e7e1502..21c0047eb5 100644
--- a/Octokit/Helpers/AcceptHeaders.cs
+++ b/Octokit/Helpers/AcceptHeaders.cs
@@ -13,5 +13,7 @@ public static class AcceptHeaders
         public const string ProtectedBranchesApiPreview = "application/vnd.github.loki-preview+json";
 
         public const string StarCreationTimestamps = "application/vnd.github.v3.star+json";
+
+        public const string CommitReferenceSha1Preview = "application/vnd.github.chitauri-preview+sha";
     }
 }