diff --git a/jwk.go b/jwk.go
index ccdfb2e8..59d9a924 100644
--- a/jwk.go
+++ b/jwk.go
@@ -21,6 +21,8 @@ import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rsa"
+	"crypto/x509"
+	"encoding/base64"
 	"fmt"
 	"math/big"
 	"reflect"
@@ -49,14 +51,17 @@ type rawJsonWebKey struct {
 	Dp *byteBuffer `json:"dp,omitempty"`
 	Dq *byteBuffer `json:"dq,omitempty"`
 	Qi *byteBuffer `json:"qi,omitempty"`
+	// Certificates
+	X5c []string `json:"x5c,omitempty"`
 }
 
 // JsonWebKey represents a public or private key in JWK format.
 type JsonWebKey struct {
-	Key       interface{}
-	KeyID     string
-	Algorithm string
-	Use       string
+	Key          interface{}
+	Certificates []*x509.Certificate
+	KeyID        string
+	Algorithm    string
+	Use          string
 }
 
 // MarshalJSON serializes the given key to its JSON representation.
@@ -87,6 +92,10 @@ func (k JsonWebKey) MarshalJSON() ([]byte, error) {
 	raw.Alg = k.Algorithm
 	raw.Use = k.Use
 
+	for _, cert := range k.Certificates {
+		raw.X5c = append(raw.X5c, base64.StdEncoding.EncodeToString(cert.Raw))
+	}
+
 	return MarshalJSON(raw)
 }
 
@@ -121,6 +130,19 @@ func (k *JsonWebKey) UnmarshalJSON(data []byte) (err error) {
 	if err == nil {
 		*k = JsonWebKey{Key: key, KeyID: raw.Kid, Algorithm: raw.Alg, Use: raw.Use}
 	}
+
+	k.Certificates = make([]*x509.Certificate, len(raw.X5c))
+	for i, cert := range raw.X5c {
+		raw, err := base64.StdEncoding.DecodeString(cert)
+		if err != nil {
+			return err
+		}
+		k.Certificates[i], err = x509.ParseCertificate(raw)
+		if err != nil {
+			return err
+		}
+	}
+
 	return
 }
 
diff --git a/jwk_test.go b/jwk_test.go
index a87b42a1..9ea7b451 100644
--- a/jwk_test.go
+++ b/jwk_test.go
@@ -22,6 +22,7 @@ import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rsa"
+	"crypto/x509"
 	"encoding/hex"
 	"fmt"
 	"math/big"
@@ -29,6 +30,48 @@ import (
 	"testing"
 )
 
+// Test chain of two X.509 certificates
+var testCertificates, _ = x509.ParseCertificates(fromBase64Bytes(`
+MIIDfDCCAmSgAwIBAgIJANWAkzF7PA8/MA0GCSqGSIb3DQEBCwUAMFUxCzAJ
+BgNVBAYTAlVTMQswCQYDVQQIEwJDQTEQMA4GA1UEChMHY2VydGlnbzEQMA4G
+A1UECxMHZXhhbXBsZTEVMBMGA1UEAxMMZXhhbXBsZS1sZWFmMB4XDTE2MDYx
+MDIyMTQxMVoXDTIzMDQxNTIyMTQxMVowVTELMAkGA1UEBhMCVVMxCzAJBgNV
+BAgTAkNBMRAwDgYDVQQKEwdjZXJ0aWdvMRAwDgYDVQQLEwdleGFtcGxlMRUw
+EwYDVQQDEwxleGFtcGxlLWxlYWYwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAw
+ggEKAoIBAQC7stSvfQyGuHw3v34fisqIdDXberrFoFk9ht/WdXgYzX2uLNKd
+sR/J5sbWSl8K/5djpzj31eIzqU69w8v7SChM5x9bouDsABHz3kZucx5cSafE
+gJojysBkcrq3VY+aJanzbL+qErYX+lhRpPcZK6JMWIwar8Y3B2la4yWwieec
+w2/WfEVvG0M/DOYKnR8QHFsfl3US1dnBM84czKPyt9r40gDk2XiH/lGts5a9
+4rAGvbr8IMCtq0mA5aH3Fx3mDSi3+4MZwygCAHrF5O5iSV9rEI+m2+7j2S+j
+HDUnvV+nqcpb9m6ENECnYX8FD2KcqlOjTmw8smDy09N2Np6i464lAgMBAAGj
+TzBNMB0GA1UdJQQWMBQGCCsGAQUFBwMCBggrBgEFBQcDATAsBgNVHREEJTAj
+hwR/AAABhxAAAAAAAAAAAAAAAAAAAAABgglsb2NhbGhvc3QwDQYJKoZIhvcN
+AQELBQADggEBAGM4aa/qrURUweZBIwZYv8O9b2+r4l0HjGAh982/B9sMlM05
+kojyDCUGvj86z18Lm8mKr4/y+i0nJ+vDIksEvfDuzw5ALAXGcBzPJKtICUf7
+LstA/n9NNpshWz0kld9ylnB5mbUzSFDncVyeXkEf5sGQXdIIZT9ChRBoiloS
+aa7dvBVCcsX1LGP2LWqKtD+7nUnw5qCwtyAVT8pthEUxFTpywoiJS5ZdzeEx
+8MNGvUeLFj2kleqPF78EioEQlSOxViCuctEtnQuPcDLHNFr10byTZY9roObi
+qdsJLMVvb2XliJjAqaPa9AkYwGE6xHw2ispwg64Rse0+AtKups19WIUwggNT
+MIICO6ADAgECAgkAqD4tCWKt9/AwDQYJKoZIhvcNAQELBQAwVTELMAkGA1UE
+BhMCVVMxCzAJBgNVBAgTAkNBMRAwDgYDVQQKEwdjZXJ0aWdvMRAwDgYDVQQL
+EwdleGFtcGxlMRUwEwYDVQQDEwxleGFtcGxlLXJvb3QwHhcNMTYwNjEwMjIx
+NDExWhcNMjMwNDE1MjIxNDExWjBVMQswCQYDVQQGEwJVUzELMAkGA1UECBMC
+Q0ExEDAOBgNVBAoTB2NlcnRpZ28xEDAOBgNVBAsTB2V4YW1wbGUxFTATBgNV
+BAMTDGV4YW1wbGUtcm9vdDCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoC
+ggEBAMo4ShKI2MxDz/NQVxBbz0tbD5R5NcobA0NKkaPKLyMEpnWVY9ucyauM
+joNn1F568cfOoF0pm3700U8UTPt2MMxEHIi4mFG/OF8UF+Voh1J42Tb42lRo
+W5RRR3ogh4+7QB1G94nxkYddHAJ4QMhUJlLigFg8c6Ff/MxYODy9I7ilLFOM
+Zzsjx8fFpRKRXNQFt471P/V4WTSba7GzdTOJRyTZf/xipF36n8RoEQPvyde8
+pEAsCC4oDOrEiCTdxw8rRJVAU0Wr55XX+qjxyi55C6oykIC/BWR+lUqGd7IL
+Y2Uyt/OVxllt8b+KuVKNCfn4TFlfgizLWkJRs6JV9KuwJ20CAwEAAaMmMCQw
+DgYDVR0PAQH/BAQDAgIEMBIGA1UdEwEB/wQIMAYBAf8CAQAwDQYJKoZIhvcN
+AQELBQADggEBAIsQlTrm9NT6gts0cs4JHp8AutuMrvGyLpIUOlJcEybvgxaz
+LebIMGZek5w3yEJiCyCK9RdNDP3Kdc/+nM6PhvzfPOVo58+0tMCYyEpZVXhD
+zmasNDP4fMbiUpczvx5OwPw/KuhwD+1ITuZUQnQlqXgTYoj9n39+qlgUsHos
+WXHmfzd6Fcz96ADSXg54IL2cEoJ41Q3ewhA7zmWWPLMAl21aex2haiAmzqqN
+xXyfZTnGNnE3lkV1yVguOrqDZyMRdcxDFvxvtmEeMtYV2Mc/zlS9ccrcOkrc
+mZSDxthLu3UMl98NA2NrCGWwzJwpk36vQ0PRSbibsCMarFspP8zbIoU=`))
+
 func TestCurveSize(t *testing.T) {
 	size256 := curveSize(elliptic.P256())
 	size384 := curveSize(elliptic.P384())
@@ -156,6 +199,38 @@ func TestRoundtripEcPrivate(t *testing.T) {
 	}
 }
 
+func TestRoundtripX5C(t *testing.T) {
+	jwk := JsonWebKey{
+		Key:          rsaTestKey,
+		KeyID:        "bar",
+		Algorithm:    "foo",
+		Certificates: testCertificates,
+	}
+
+	jsonbar, err := jwk.MarshalJSON()
+	if err != nil {
+		t.Error("problem marshaling", err)
+	}
+
+	var jwk2 JsonWebKey
+	err = jwk2.UnmarshalJSON(jsonbar)
+	if err != nil {
+		t.Error("problem unmarshalling", err)
+	}
+
+	if !reflect.DeepEqual(testCertificates, jwk2.Certificates) {
+		t.Error("Certificates not equal", jwk.Certificates, jwk2.Certificates)
+	}
+
+	jsonbar2, err := jwk2.MarshalJSON()
+	if err != nil {
+		t.Error("problem marshaling", err)
+	}
+	if !bytes.Equal(jsonbar, jsonbar2) {
+		t.Error("roundtrip should not lose information")
+	}
+}
+
 func TestMarshalUnmarshal(t *testing.T) {
 	kid := "DEADBEEF"
 
@@ -383,6 +458,38 @@ var cookbookJWKs = []string{
       "qi":"lSQi-w9CpyUReMErP1RsBLk7wNtOvs5EQpPqmuMvqW57NBUczScEoPwmUqq
            abu9V0-Py4dQ57_bapoKRu1R90bvuFnU63SHWEFglZQvJDMeAvmj4sm-Fp0o
            Yu_neotgQ0hzbI5gry7ajdYy9-2lNx_76aBZoOUu9HCJ-UsfSOI8"}`),
+
+	// X.509 Certificate Chain
+	stripWhitespace(`{"kty":"RSA",
+      "use":"sig",
+      "kid":"1b94c",
+      "n":"vrjOfz9Ccdgx5nQudyhdoR17V-IubWMeOZCwX_jj0hgAsz2J_pqYW08
+           PLbK_PdiVGKPrqzmDIsLI7sA25VEnHU1uCLNwBuUiCO11_-7dYbsr4iJmG0Q
+           u2j8DsVyT1azpJC_NG84Ty5KKthuCaPod7iI7w0LK9orSMhBEwwZDCxTWq4a
+           YWAchc8t-emd9qOvWtVMDC2BXksRngh6X5bUYLy6AyHKvj-nUy1wgzjYQDwH
+           MTplCoLtU-o-8SNnZ1tmRoGE9uJkBLdh5gFENabWnU5m1ZqZPdwS-qo-meMv
+           VfJb6jJVWRpl2SUtCnYG2C32qvbWbjZ_jBPD5eunqsIo1vQ",
+      "e":"AQAB",
+      "x5c":
+           ["MIIDQjCCAiqgAwIBAgIGATz/FuLiMA0GCSqGSIb3DQEBBQUAMGIxCzAJB
+           gNVBAYTAlVTMQswCQYDVQQIEwJDTzEPMA0GA1UEBxMGRGVudmVyMRwwGgYD
+           VQQKExNQaW5nIElkZW50aXR5IENvcnAuMRcwFQYDVQQDEw5CcmlhbiBDYW1
+           wYmVsbDAeFw0xMzAyMjEyMzI5MTVaFw0xODA4MTQyMjI5MTVaMGIxCzAJBg
+           NVBAYTAlVTMQswCQYDVQQIEwJDTzEPMA0GA1UEBxMGRGVudmVyMRwwGgYDV
+           QQKExNQaW5nIElkZW50aXR5IENvcnAuMRcwFQYDVQQDEw5CcmlhbiBDYW1w
+           YmVsbDCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAL64zn8/QnH
+           YMeZ0LncoXaEde1fiLm1jHjmQsF/449IYALM9if6amFtPDy2yvz3YlRij66
+           s5gyLCyO7ANuVRJx1NbgizcAblIgjtdf/u3WG7K+IiZhtELto/A7Fck9Ws6
+           SQvzRvOE8uSirYbgmj6He4iO8NCyvaK0jIQRMMGQwsU1quGmFgHIXPLfnpn
+           fajr1rVTAwtgV5LEZ4Iel+W1GC8ugMhyr4/p1MtcIM42EA8BzE6ZQqC7VPq
+           PvEjZ2dbZkaBhPbiZAS3YeYBRDWm1p1OZtWamT3cEvqqPpnjL1XyW+oyVVk
+           aZdklLQp2Btgt9qr21m42f4wTw+Xrp6rCKNb0CAwEAATANBgkqhkiG9w0BA
+           QUFAAOCAQEAh8zGlfSlcI0o3rYDPBB07aXNswb4ECNIKG0CETTUxmXl9KUL
+           +9gGlqCz5iWLOgWsnrcKcY0vXPG9J1r9AqBNTqNgHq2G03X09266X5CpOe1
+           zFo+Owb1zxtp3PehFdfQJ610CDLEaS9V9Rqp17hCyybEpOGVwe8fnk+fbEL
+           2Bo3UPGrpsHzUoaGpDftmWssZkhpBJKVMJyf/RuP2SmmaIzmnw9JiSlYhzo
+           4tpzd5rFXhjRbg4zW9C+2qok+2+qDM1iJ684gPHMIY8aLWrdgQTxkumGmTq
+           gawR+N5MDtdPTEQ0XfIBc2cJEUyMTY5MPvACWpkA6SdS4xSvdXK3IVfOWA=="]}`),
 }
 
 // SHA-256 thumbprints of the above keys, hex-encoded
@@ -391,6 +498,7 @@ var cookbookJWKThumbprints = []string{
 	"747ae2dd2003664aeeb21e4753fe7402846170a16bc8df8f23a8cf06d3cbe793",
 	"f63838e96077ad1fc01c3f8405774dedc0641f558ebb4b40dccf5f9b6d66a932",
 	"0fc478f8579325fcee0d4cbc6d9d1ce21730a6e97e435d6008fb379b0ebe47d4",
+	"0ddb05bfedbec2070fa037324ba397396561d3425d6d69245570c261dc49dee3",
 }
 
 func TestWebKeyVectorsValid(t *testing.T) {