diff --git a/expfmt/text_parse.go b/expfmt/text_parse.go
index ec3d86ba7..77f8cee73 100644
--- a/expfmt/text_parse.go
+++ b/expfmt/text_parse.go
@@ -99,6 +99,13 @@ type TextParser struct {
 // input concurrently, instantiate a separate Parser for each goroutine.
 func (p *TextParser) TextToMetricFamilies(in io.Reader) (map[string]*dto.MetricFamily, error) {
 	p.reset(in)
+
+	// Some clients might throw in Unicode BOM chars which is explicitly forbidden.
+	if bomType := p.hasBOM(); bomType != "" {
+		p.parseError(bomType + " BOM detected but not supported")
+		return p.metricFamiliesByName, p.err
+	}
+
 	for nextState := p.startOfLine; nextState != nil; nextState = nextState() {
 		// Magic happens here...
 	}
@@ -118,6 +125,31 @@ func (p *TextParser) TextToMetricFamilies(in io.Reader) (map[string]*dto.MetricF
 	return p.metricFamiliesByName, p.err
 }
 
+func (p *TextParser) hasBOM() string {
+	maybeBOM, err := p.buf.Peek(4)
+
+	// Can't read, no BOM found.
+	if err != nil {
+		return ""
+	}
+	// UTF-32 BOM.
+	if len(maybeBOM) == 4 &&
+		((maybeBOM[0] == 0x00 && maybeBOM[1] == 0x00 && maybeBOM[2] == 0xFE && maybeBOM[3] == 0xFF) ||
+			(maybeBOM[0] == 0xFF && maybeBOM[1] == 0xFE && maybeBOM[2] == 0x00 && maybeBOM[3] == 0x00)) {
+		return "UTF-32"
+	}
+	// UTF-16 BOM.
+	if len(maybeBOM) >= 2 && ((maybeBOM[0] == 0xFE && maybeBOM[1] == 0xFF) || (maybeBOM[0] == 0xFF && maybeBOM[1] == 0xFE)) {
+		return "UTF-16"
+	}
+	// UTF-8 BOM.
+	if len(maybeBOM) >= 3 && maybeBOM[0] == 0xEF && maybeBOM[1] == 0xBB && maybeBOM[2] == 0xBF {
+		return "UTF-8"
+	}
+	// No BOM.
+	return ""
+}
+
 func (p *TextParser) reset(in io.Reader) {
 	p.metricFamiliesByName = map[string]*dto.MetricFamily{}
 	if p.buf == nil {
diff --git a/expfmt/text_parse_test.go b/expfmt/text_parse_test.go
index 76c951185..569ceebc9 100644
--- a/expfmt/text_parse_test.go
+++ b/expfmt/text_parse_test.go
@@ -564,6 +564,31 @@ metric_bucket{le="bla"} 3.14
 			in:  "metric{l=\"\xbd\"} 3.14\n",
 			err: "text format parsing error in line 1: invalid label value \"\\xbd\"",
 		},
+		// 20: UTF-8 BOM present.
+		{
+			in:  "\xef\xbb\xbfafter_utf8_bom 1\n",
+			err: "text format parsing error in line 0: UTF-8 BOM detected but not supported",
+		},
+		// 21: UTF-16 LE BOM present.
+		{
+			in:  "\xfe\xffafter_utf16le_bom 1\n",
+			err: "text format parsing error in line 0: UTF-16 BOM detected but not supported",
+		},
+		// 22: UTF-16 BE BOM present.
+		{
+			in:  "\xff\xfeafter_utf16be_bom 1\n",
+			err: "text format parsing error in line 0: UTF-16 BOM detected but not supported",
+		},
+		// 23: UTF-32 LE BOM present.
+		{
+			in:  "\xff\xfe\x00\x00after_utf32le_bom 1\n",
+			err: "text format parsing error in line 0: UTF-32 BOM detected but not supported",
+		},
+		// 24: UTF-32 BE BOM present.
+		{
+			in:  "\x00\x00\xfe\xffafter_utf32be_bom 1\n",
+			err: "text format parsing error in line 0: UTF-32 BOM detected but not supported",
+		},
 	}
 
 	for i, scenario := range scenarios {