diff --git a/esphome/components/http_request/http_request.h b/esphome/components/http_request/http_request.h
index dacf691d38..06c87bb4ab 100644
--- a/esphome/components/http_request/http_request.h
+++ b/esphome/components/http_request/http_request.h
@@ -374,7 +374,12 @@ class HttpRequestComponent : public Component {
   std::shared_ptr<HttpContainer> start(const std::string &url, const std::string &method, const std::string &body,
                                        const std::list<Header> &request_headers,
                                        const std::vector<std::string> &collect_headers) {
-    return this->perform(url, method, body, request_headers, collect_headers);
+    std::vector<std::string> lower_case_collect_headers;
+    lower_case_collect_headers.reserve(collect_headers.size());
+    for (const auto &header : collect_headers) {
+      lower_case_collect_headers.push_back(str_lower_case(header));
+    }
+    return this->perform(url, method, body, request_headers, lower_case_collect_headers);
   }
 
  protected: