diff --git a/model/textparse/protobufparse.go b/model/textparse/protobufparse.go
index 37c6f0ebb..003f88456 100644
--- a/model/textparse/protobufparse.go
+++ b/model/textparse/protobufparse.go
@@ -105,7 +105,7 @@ func (p *ProtobufParser) Series() ([]byte, *int64, float64) {
 		default:
 			v = s.GetQuantile()[p.fieldPos].GetValue()
 		}
-	case dto.MetricType_HISTOGRAM:
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 		// This should only happen for a legacy histogram.
 		h := m.GetHistogram()
 		switch p.fieldPos {
@@ -225,6 +225,8 @@ func (p *ProtobufParser) Type() ([]byte, MetricType) {
 		return n, MetricTypeGauge
 	case dto.MetricType_HISTOGRAM:
 		return n, MetricTypeHistogram
+	case dto.MetricType_GAUGE_HISTOGRAM:
+		return n, MetricTypeGaugeHistogram
 	case dto.MetricType_SUMMARY:
 		return n, MetricTypeSummary
 	}
@@ -273,7 +275,7 @@ func (p *ProtobufParser) Exemplar(ex *exemplar.Exemplar) bool {
 	switch p.mf.GetType() {
 	case dto.MetricType_COUNTER:
 		exProto = m.GetCounter().GetExemplar()
-	case dto.MetricType_HISTOGRAM:
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 		bb := m.GetHistogram().GetBucket()
 		if p.fieldPos < 0 {
 			if p.state == EntrySeries {
@@ -331,7 +333,7 @@ func (p *ProtobufParser) Next() (Entry, error) {
 		}
 
 		// We are at the beginning of a metric family. Put only the name
-		// into metricBytes and validate only name and help for now.
+		// into metricBytes and validate only name, help, and type for now.
 		name := p.mf.GetName()
 		if !model.IsValidMetricName(model.LabelValue(name)) {
 			return EntryInvalid, errors.Errorf("invalid metric name: %s", name)
@@ -339,6 +341,17 @@ func (p *ProtobufParser) Next() (Entry, error) {
 		if help := p.mf.GetHelp(); !utf8.ValidString(help) {
 			return EntryInvalid, errors.Errorf("invalid help for metric %q: %s", name, help)
 		}
+		switch p.mf.GetType() {
+		case dto.MetricType_COUNTER,
+			dto.MetricType_GAUGE,
+			dto.MetricType_HISTOGRAM,
+			dto.MetricType_GAUGE_HISTOGRAM,
+			dto.MetricType_SUMMARY,
+			dto.MetricType_UNTYPED:
+			// All good.
+		default:
+			return EntryInvalid, errors.Errorf("unknown metric type for metric %q: %s", name, p.mf.GetType())
+		}
 		p.metricBytes.Reset()
 		p.metricBytes.WriteString(name)
 
@@ -346,7 +359,8 @@ func (p *ProtobufParser) Next() (Entry, error) {
 	case EntryHelp:
 		p.state = EntryType
 	case EntryType:
-		if p.mf.GetType() == dto.MetricType_HISTOGRAM &&
+		t := p.mf.GetType()
+		if (t == dto.MetricType_HISTOGRAM || t == dto.MetricType_GAUGE_HISTOGRAM) &&
 			isNativeHistogram(p.mf.GetMetric()[0].GetHistogram()) {
 			p.state = EntryHistogram
 		} else {
@@ -356,8 +370,11 @@ func (p *ProtobufParser) Next() (Entry, error) {
 			return EntryInvalid, err
 		}
 	case EntryHistogram, EntrySeries:
+		t := p.mf.GetType()
 		if p.state == EntrySeries && !p.fieldsDone &&
-			(p.mf.GetType() == dto.MetricType_SUMMARY || p.mf.GetType() == dto.MetricType_HISTOGRAM) {
+			(t == dto.MetricType_SUMMARY ||
+				t == dto.MetricType_HISTOGRAM ||
+				t == dto.MetricType_GAUGE_HISTOGRAM) {
 			p.fieldPos++
 		} else {
 			p.metricPos++
@@ -418,7 +435,7 @@ func (p *ProtobufParser) getMagicName() string {
 	if p.fieldPos == -1 {
 		return p.mf.GetName() + "_sum"
 	}
-	if t == dto.MetricType_HISTOGRAM {
+	if t == dto.MetricType_HISTOGRAM || t == dto.MetricType_GAUGE_HISTOGRAM {
 		return p.mf.GetName() + "_bucket"
 	}
 	return p.mf.GetName()
@@ -436,7 +453,7 @@ func (p *ProtobufParser) getMagicLabel() (bool, string, string) {
 		q := qq[p.fieldPos]
 		p.fieldsDone = p.fieldPos == len(qq)-1
 		return true, model.QuantileLabel, formatOpenMetricsFloat(q.GetQuantile())
-	case dto.MetricType_HISTOGRAM:
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 		bb := p.mf.GetMetric()[p.metricPos].GetHistogram().GetBucket()
 		if p.fieldPos >= len(bb) {
 			p.fieldsDone = true