diff --git a/xlsx/sheets.go b/xlsx/sheets.go
index fc9c76b..fa7b499 100644
--- a/xlsx/sheets.go
+++ b/xlsx/sheets.go
@@ -33,7 +33,7 @@ func (s *Sheet) parseSheet() error {
 	linkmap := make(map[string]string)
 	base := filepath.Base(s.docname)
 	sub := strings.TrimSuffix(s.docname, base)
-	relsname := filepath.Join(sub, "_rels", base+".rels")
+	relsname := strings.ReplaceAll(filepath.Join(sub, "_rels", base+".rels"), "\\", "/") // fix the sep in zip file is still "/" but on windows is "\"
 	dec, clo, err := s.d.openXML(relsname)
 	if err == nil {
 		// rels might not exist for every sheet
diff --git a/xlsx/workbook.go b/xlsx/workbook.go
index d789562..b8f33f7 100644
--- a/xlsx/workbook.go
+++ b/xlsx/workbook.go
@@ -32,7 +32,7 @@ func (d *Document) parseRels(dec *xml.Decoder, basedir string) error {
 					// handle malformed "absolute" paths cleanly
 					d.rels[vals["Type"]][vals["Id"]] = vals["Target"][1:]
 				} else {
-					d.rels[vals["Type"]][vals["Id"]] = filepath.Join(basedir, vals["Target"])
+					d.rels[vals["Type"]][vals["Id"]] = strings.ReplaceAll(filepath.Join(basedir, vals["Target"]), "\\", "/") // fix EOF in windows for sep being "\" instead of "/"
 				}
 				if vals["Type"] == "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" {
 					d.primaryDoc = vals["Target"]
diff --git a/xlsx/xlsx.go b/xlsx/xlsx.go
index 3d5eaad..4a6ff3c 100644
--- a/xlsx/xlsx.go
+++ b/xlsx/xlsx.go
@@ -79,7 +79,7 @@ func Open(filename string) (grate.Source, error) {
 	// parse the secondary relationships to primary doc
 	base := filepath.Base(d.primaryDoc)
 	sub := strings.TrimSuffix(d.primaryDoc, base)
-	relfn := filepath.Join(sub, "_rels", base+".rels")
+	relfn := strings.ReplaceAll(filepath.Join(sub, "_rels", base+".rels"), "\\", "/") // fix EOF in windows for sep being "\" instead of "/"
 	dec, c, err = d.openXML(relfn)
 	if err != nil {
 		return nil, err