diff --git a/models/issue_watch.go b/models/issue_watch.go
index 6144d6cafe..5b87f3599f 100644
--- a/models/issue_watch.go
+++ b/models/issue_watch.go
@@ -64,14 +64,18 @@ func getIssueWatch(e Engine, userID, issueID int64) (iw *IssueWatch, exists bool
 	return
 }
 
-// GetIssueWatchersIDs returns IDs of subscribers to a given issue id
+// GetIssueWatchersIDs returns IDs of subscribers or explicit unsubscribers to a given issue id
 // but avoids joining with `user` for performance reasons
 // User permissions must be verified elsewhere if required
-func GetIssueWatchersIDs(issueID int64) ([]int64, error) {
+func GetIssueWatchersIDs(issueID int64, watching bool) ([]int64, error) {
+	return getIssueWatchersIDs(x, issueID, watching)
+}
+
+func getIssueWatchersIDs(e Engine, issueID int64, watching bool) ([]int64, error) {
 	ids := make([]int64, 0, 64)
-	return ids, x.Table("issue_watch").
+	return ids, e.Table("issue_watch").
 		Where("issue_id=?", issueID).
-		And("is_watching = ?", true).
+		And("is_watching = ?", watching).
 		Select("user_id").
 		Find(&ids)
 }
diff --git a/services/mailer/mail_issue.go b/services/mailer/mail_issue.go
index 696adfadda..1030a9548e 100644
--- a/services/mailer/mail_issue.go
+++ b/services/mailer/mail_issue.go
@@ -62,7 +62,7 @@ func mailIssueCommentToParticipants(ctx *mailCommentContext, mentions []int64) e
 	unfiltered = append(unfiltered, ids...)
 
 	// =========== Issue watchers ===========
-	ids, err = models.GetIssueWatchersIDs(ctx.Issue.ID)
+	ids, err = models.GetIssueWatchersIDs(ctx.Issue.ID, true)
 	if err != nil {
 		return fmt.Errorf("GetIssueWatchersIDs(%d): %v", ctx.Issue.ID, err)
 	}
@@ -80,6 +80,14 @@ func mailIssueCommentToParticipants(ctx *mailCommentContext, mentions []int64) e
 
 	// Avoid mailing the doer
 	visited[ctx.Doer.ID] = true
+	// Avoid mailing explicit unwatched
+	ids, err = models.GetIssueWatchersIDs(ctx.Issue.ID, false)
+	if err != nil {
+		return fmt.Errorf("GetIssueWatchersIDs(%d): %v", ctx.Issue.ID, err)
+	}
+	for _, i := range ids {
+		visited[i] = true
+	}
 
 	if err = mailIssueCommentBatch(ctx, unfiltered, visited, false); err != nil {
 		return fmt.Errorf("mailIssueCommentBatch(): %v", err)