diff --git a/SwiftGit2.xcodeproj/project.pbxproj b/SwiftGit2.xcodeproj/project.pbxproj
index ba52b15..7546a65 100644
--- a/SwiftGit2.xcodeproj/project.pbxproj
+++ b/SwiftGit2.xcodeproj/project.pbxproj
@@ -15,6 +15,8 @@
 		BE244A4E1A11707D00F8BE42 /* git2.h in Headers */ = {isa = PBXBuildFile; fileRef = BEB31F9B1A0E581400F525B9 /* git2.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		BE244A501A11709600F8BE42 /* git2 in Resources */ = {isa = PBXBuildFile; fileRef = BE244A4F1A11709600F8BE42 /* git2 */; };
 		BE244A511A11709E00F8BE42 /* git2 in Copy libgit2 Headers */ = {isa = PBXBuildFile; fileRef = BE244A4F1A11709600F8BE42 /* git2 */; };
+		BE70B3E51A1ACB1A002C3F4E /* OID.swift in Sources */ = {isa = PBXBuildFile; fileRef = BE70B3E41A1ACB1A002C3F4E /* OID.swift */; };
+		BE70B3E71A1ACB37002C3F4E /* OIDSpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = BE70B3E61A1ACB37002C3F4E /* OIDSpec.swift */; };
 		BEB31F291A0D6F7A00F525B9 /* SwiftGit2.h in Headers */ = {isa = PBXBuildFile; fileRef = BEB31F281A0D6F7A00F525B9 /* SwiftGit2.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		BEB31F2F1A0D6F7A00F525B9 /* SwiftGit2.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = BEB31F231A0D6F7A00F525B9 /* SwiftGit2.framework */; };
 		BEB31F361A0D6F7A00F525B9 /* RepositorySpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEB31F351A0D6F7A00F525B9 /* RepositorySpec.swift */; };
@@ -64,6 +66,8 @@
 		BE14AA581A1996B70015B439 /* FixturesSpec.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FixturesSpec.swift; sourceTree = "<group>"; };
 		BE244A4F1A11709600F8BE42 /* git2 */ = {isa = PBXFileReference; lastKnownFileType = folder; name = git2; path = External/libgit2/include/git2; sourceTree = "<group>"; };
 		BE244A521A117DA100F8BE42 /* SwiftGit2.modulemap */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = "sourcecode.module-map"; path = SwiftGit2.modulemap; sourceTree = "<group>"; };
+		BE70B3E41A1ACB1A002C3F4E /* OID.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OID.swift; sourceTree = "<group>"; };
+		BE70B3E61A1ACB37002C3F4E /* OIDSpec.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OIDSpec.swift; sourceTree = "<group>"; };
 		BEB31F231A0D6F7A00F525B9 /* SwiftGit2.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = SwiftGit2.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		BEB31F271A0D6F7A00F525B9 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		BEB31F281A0D6F7A00F525B9 /* SwiftGit2.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SwiftGit2.h; sourceTree = "<group>"; };
@@ -157,6 +161,7 @@
 			children = (
 				BEB31F281A0D6F7A00F525B9 /* SwiftGit2.h */,
 				BE14AA4F1A1974010015B439 /* SwiftGit2.m */,
+				BE70B3E41A1ACB1A002C3F4E /* OID.swift */,
 				BEB31F6C1A0D78F300F525B9 /* Repository.swift */,
 				BEB31F261A0D6F7A00F525B9 /* Supporting Files */,
 			);
@@ -176,6 +181,7 @@
 			isa = PBXGroup;
 			children = (
 				BE14AA531A1983520015B439 /* Fixtures */,
+				BE70B3E61A1ACB37002C3F4E /* OIDSpec.swift */,
 				BEB31F351A0D6F7A00F525B9 /* RepositorySpec.swift */,
 				BE14AA581A1996B70015B439 /* FixturesSpec.swift */,
 				BEB31F331A0D6F7A00F525B9 /* Supporting Files */,
@@ -425,6 +431,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				BE70B3E51A1ACB1A002C3F4E /* OID.swift in Sources */,
 				BEB31F6D1A0D78F300F525B9 /* Repository.swift in Sources */,
 				BE14AA501A1974010015B439 /* SwiftGit2.m in Sources */,
 			);
@@ -437,6 +444,7 @@
 				BEB31F361A0D6F7A00F525B9 /* RepositorySpec.swift in Sources */,
 				BE14AA591A1996B70015B439 /* FixturesSpec.swift in Sources */,
 				BE14AA551A1984550015B439 /* Fixtures.swift in Sources */,
+				BE70B3E71A1ACB37002C3F4E /* OIDSpec.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/SwiftGit2/OID.swift b/SwiftGit2/OID.swift
new file mode 100644
index 0000000..6352ca4
--- /dev/null
+++ b/SwiftGit2/OID.swift
@@ -0,0 +1,52 @@
+//
+//  OID.swift
+//  SwiftGit2
+//
+//  Created by Matt Diephouse on 11/17/14.
+//  Copyright (c) 2014 GitHub, Inc. All rights reserved.
+//
+
+import Foundation
+import LlamaKit
+
+/// An identifier for a Git object.
+public struct OID {
+	
+	// MARK: - Initializers
+	
+	/// Create an instance from a hex formatted string.
+	///
+	/// string - A 40-byte hex formatted string.
+	public init?(string: String) {
+		// libgit2 doesn't enforce a maximum length
+		if (string.lengthOfBytesUsingEncoding(NSASCIIStringEncoding) > 40) {
+			return nil
+		}
+		
+		let pointer = UnsafeMutablePointer<git_oid>.alloc(1)
+		let result = git_oid_fromstr(pointer, string.cStringUsingEncoding(NSASCIIStringEncoding)!)
+		
+		if result < GIT_OK.value {
+			pointer.dealloc(1)
+			return nil;
+		}
+		
+		oid = pointer.memory;
+		pointer.dealloc(1)
+	}
+	
+	// MARK: - Properties
+	
+	public let oid: git_oid
+}
+
+extension OID: Printable {
+	public var description: String {
+		let length = Int(GIT_OID_RAWSZ) * 2
+		let string = UnsafeMutablePointer<Int8>.alloc(length)
+		var oid = self.oid
+		git_oid_fmt(string, &oid)
+		
+		return String(bytesNoCopy: string, length: length, encoding: NSASCIIStringEncoding, freeWhenDone: true)!
+	}
+}
diff --git a/SwiftGit2Tests/OIDSpec.swift b/SwiftGit2Tests/OIDSpec.swift
new file mode 100644
index 0000000..fe8c3ae
--- /dev/null
+++ b/SwiftGit2Tests/OIDSpec.swift
@@ -0,0 +1,42 @@
+//
+//  OIDSpec.swift
+//  SwiftGit2
+//
+//  Created by Matt Diephouse on 11/17/14.
+//  Copyright (c) 2014 GitHub, Inc. All rights reserved.
+//
+
+import LlamaKit
+import SwiftGit2
+import Nimble
+import Quick
+
+class OIDSpec: QuickSpec {
+	override func spec() {
+		describe("init(string:)") {
+			it("should be nil if string is too short") {
+				expect(OID(string: "123456789012345678901234567890123456789")).to(beNil())
+			}
+
+			it("should be nil if string is too long") {
+				expect(OID(string: "12345678901234567890123456789012345678901")).to(beNil())
+			}
+
+			it("should not be nil if string is just right") {
+				expect(OID(string: "1234567890123456789012345678901234567890")).notTo(beNil())
+			}
+			
+			it("should be nil with non-hex characters") {
+				expect(OID(string: "123456789012345678901234567890123456789j")).to(beNil())
+			}
+		}
+		
+		describe("description") {
+			it("should return the SHA") {
+				let SHA = "1234567890123456789012345678901234567890"
+				let oid = OID(string: SHA)!
+				expect(oid.description).to(equal(SHA))
+			}
+		}
+	}
+}