diff --git a/event/content.go b/event/content.go
index 464620d4..18541392 100644
--- a/event/content.go
+++ b/event/content.go
@@ -67,6 +67,14 @@ var TypeMap = map[Type]reflect.Type{
 	ToDeviceVerificationRequest: reflect.TypeOf(VerificationRequestEventContent{}),
 
 	ToDeviceOrgMatrixRoomKeyWithheld: reflect.TypeOf(RoomKeyWithheldEventContent{}),
+
+	CallInvite:       reflect.TypeOf(CallInviteEventContent{}),
+	CallCandidates:   reflect.TypeOf(CallCandidatesEventContent{}),
+	CallAnswer:       reflect.TypeOf(CallAnswerEventContent{}),
+	CallReject:       reflect.TypeOf(CallRejectEventContent{}),
+	CallSelectAnswer: reflect.TypeOf(CallSelectAnswerEventContent{}),
+	CallNegotiate:    reflect.TypeOf(CallNegotiateEventContent{}),
+	CallHangup:       reflect.TypeOf(CallHangupEventContent{}),
 }
 
 // Content stores the content of a Matrix event.
@@ -398,3 +406,52 @@ func (content *Content) AsRoomKeyWithheld() *RoomKeyWithheldEventContent {
 	}
 	return casted
 }
+func (content *Content) AsCallInvite() *CallInviteEventContent {
+	casted, ok := content.Parsed.(*CallInviteEventContent)
+	if !ok {
+		return &CallInviteEventContent{}
+	}
+	return casted
+}
+func (content *Content) AsCallCandidates() *CallCandidatesEventContent {
+	casted, ok := content.Parsed.(*CallCandidatesEventContent)
+	if !ok {
+		return &CallCandidatesEventContent{}
+	}
+	return casted
+}
+func (content *Content) AsCallAnswer() *CallAnswerEventContent {
+	casted, ok := content.Parsed.(*CallAnswerEventContent)
+	if !ok {
+		return &CallAnswerEventContent{}
+	}
+	return casted
+}
+func (content *Content) AsCallReject() *CallRejectEventContent {
+	casted, ok := content.Parsed.(*CallRejectEventContent)
+	if !ok {
+		return &CallRejectEventContent{}
+	}
+	return casted
+}
+func (content *Content) AsCallSelectAnswer() *CallSelectAnswerEventContent {
+	casted, ok := content.Parsed.(*CallSelectAnswerEventContent)
+	if !ok {
+		return &CallSelectAnswerEventContent{}
+	}
+	return casted
+}
+func (content *Content) AsCallNegotiate() *CallNegotiateEventContent {
+	casted, ok := content.Parsed.(*CallNegotiateEventContent)
+	if !ok {
+		return &CallNegotiateEventContent{}
+	}
+	return casted
+}
+func (content *Content) AsCallHangup() *CallHangupEventContent {
+	casted, ok := content.Parsed.(*CallHangupEventContent)
+	if !ok {
+		return &CallHangupEventContent{}
+	}
+	return casted
+}
diff --git a/event/type.go b/event/type.go
index ae144650..01b608a1 100644
--- a/event/type.go
+++ b/event/type.go
@@ -83,6 +83,16 @@ func (et *Type) IsInRoomVerification() bool {
 	}
 }
 
+func (et *Type) IsCall() bool {
+	switch et.Type {
+	case CallInvite.Type, CallCandidates.Type, CallAnswer.Type, CallReject.Type, CallSelectAnswer.Type,
+		CallNegotiate.Type, CallHangup.Type:
+		return true
+	default:
+		return false
+	}
+}
+
 func (et *Type) IsCustom() bool {
 	return !strings.HasPrefix(et.Type, "m.")
 }
@@ -173,6 +183,14 @@ var (
 	InRoomVerificationKey    = Type{"m.key.verification.key", MessageEventType}
 	InRoomVerificationMAC    = Type{"m.key.verification.mac", MessageEventType}
 	InRoomVerificationCancel = Type{"m.key.verification.cancel", MessageEventType}
+
+	CallInvite       = Type{"m.call.invite", MessageEventType}
+	CallCandidates   = Type{"m.call.candidates", MessageEventType}
+	CallAnswer       = Type{"m.call.answer", MessageEventType}
+	CallReject       = Type{"m.call.reject", MessageEventType}
+	CallSelectAnswer = Type{"m.call.select_answer", MessageEventType}
+	CallNegotiate    = Type{"m.call.negotiate", MessageEventType}
+	CallHangup       = Type{"m.call.hangup", MessageEventType}
 )
 
 // Ephemeral events
diff --git a/event/voip.go b/event/voip.go
new file mode 100644
index 00000000..e59334e7
--- /dev/null
+++ b/event/voip.go
@@ -0,0 +1,77 @@
+// Copyright (c) 2021 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package event
+
+type CallHangupReason string
+
+const (
+	CallHangupICEFailed       CallHangupReason = "ice_failed"
+	CallHangupInviteTimeout   CallHangupReason = "invite_timeout"
+	CallHangupUserHangup      CallHangupReason = "user_hangup"
+	CallHangupUserMediaFailed CallHangupReason = "user_media_failed"
+	CallHangupUnknownError    CallHangupReason = "unknown_error"
+)
+
+type CallDataType string
+
+const (
+	CallDataTypeOffer  CallDataType = "offer"
+	CallDataTypeAnswer CallDataType = "answer"
+)
+
+type CallData struct {
+	SDP  string       `json:"sdp"`
+	Type CallDataType `json:"type"`
+}
+
+type CallCandidate struct {
+	Candidate     string `json:"candidate"`
+	SDPMLineIndex int    `json:"sdpMLineIndex"`
+	SDPMID        string `json:"sdpMid"`
+}
+
+type BaseCallEventContent struct {
+	CallID  string `json:"call_id"`
+	PartyID string `json:"party_id"`
+	Version int    `json:"version"`
+}
+
+type CallInviteEventContent struct {
+	BaseCallEventContent
+	Lifetime int      `json:"lifetime"`
+	Offer    CallData `json:"offer"`
+}
+
+type CallCandidatesEventContent struct {
+	BaseCallEventContent
+	Candidates []CallCandidate `json:"candidates"`
+}
+
+type CallRejectEventContent struct {
+	BaseCallEventContent
+}
+
+type CallAnswerEventContent struct {
+	BaseCallEventContent
+	Answer CallData `json:"answer"`
+}
+
+type CallSelectAnswerEventContent struct {
+	BaseCallEventContent
+	SelectedPartyID string `json:"selected_party_id"`
+}
+
+type CallNegotiateEventContent struct {
+	BaseCallEventContent
+	Lifetime    int      `json:"lifetime"`
+	Description CallData `json:"description"`
+}
+
+type CallHangupEventContent struct {
+	BaseCallEventContent
+	Reason CallHangupReason `json:"reason"`
+}