diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4c2812160f..e25c4f5501 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,10 +11,13 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 
 ## Unreleased
 
-- [#3032](https://github.com/thanos-io/thanos/pull/3032) Query Frontend: Added support for Memacahce cache. Replaced underscores with hyphens in `log_queries_longer_than - > log-queries-longer-than`.
+### Fixed
+
+- [#3234](https://github.com/thanos-io/thanos/pull/3234) UI: Fix assets not loading when `--web.prefix-header` is used.
 
 ### Added
 
+- [#3032](https://github.com/thanos-io/thanos/pull/3032) Query Frontend: Added support for Memacahce cache. Replaced underscores with hyphens in `log_queries_longer_than - > log-queries-longer-than`.
 - [#3166](https://github.com/thanos-io/thanos/pull/3166) UIs: Added UI for passing a `storeMatch[]` parameter to queries.
 - [#3184](https://github.com/thanos-io/thanos/pull/3184) Compact: Fix web.prefix-header to use &wc.prefixHeaderName
 - [#3181](https://github.com/thanos-io/thanos/pull/3181) Logging: Add debug level logging for responses between 300-399
diff --git a/pkg/ui/ui.go b/pkg/ui/ui.go
index 4c2b9dea74..d4e2f1a506 100644
--- a/pkg/ui/ui.go
+++ b/pkg/ui/ui.go
@@ -158,7 +158,7 @@ func absolutePrefix(prefix string) func() string {
 		if prefix == "" {
 			return ""
 		}
-		return "/" + prefix
+		return path.Join("/", prefix)
 	}
 }