diff --git a/src/hackney_conn.erl b/src/hackney_conn.erl
index c2b3e796..6876b089 100644
--- a/src/hackney_conn.erl
+++ b/src/hackney_conn.erl
@@ -761,10 +761,9 @@ connected({call, From}, {upgrade_to_ssl, _SslOpts}, #conn_data{transport = hackn
     {keep_state_and_data, [{reply, From, ok}]};
 connected({call, From}, {upgrade_to_ssl, SslOpts}, #conn_data{socket = Socket, host = Host, connect_options = ConnectOpts} = Data) ->
     %% Upgrade TCP socket to SSL (e.g., after CONNECT proxy tunnel)
-    %% Get default SSL options with hostname verification
-    DefaultSslOpts = hackney_ssl:check_hostname_opts(Host),
-    %% Merge user-provided SSL options (they override defaults)
-    MergedSslOpts = hackney_util:merge_opts(DefaultSslOpts, SslOpts),
+    %% Use ssl_opts/2 to properly merge defaults with user options
+    %% (handles cacertfile vs cacerts correctly)
+    MergedSslOpts = hackney_ssl:ssl_opts(Host, [{ssl_options, SslOpts}]),
     %% Add ALPN options for HTTP/2 negotiation
     %% Check both SslOpts (from upgrade call) and ConnectOpts (from initial config)
     AlpnOpts = case hackney_ssl:alpn_opts(SslOpts) of
@@ -2271,8 +2270,9 @@ do_tcp_connect(From, Data) ->
     TransportOpts = proplists:delete(protocols, ConnectOpts),
     Opts = case Transport of
         hackney_ssl ->
-            DefaultSslOpts = hackney_ssl:check_hostname_opts(Host),
-            MergedSslOpts = hackney_util:merge_opts(DefaultSslOpts, SslOpts0),
+            %% Use ssl_opts/2 to properly merge defaults with user options
+            %% (handles cacertfile vs cacerts correctly)
+            MergedSslOpts = hackney_ssl:ssl_opts(Host, [{ssl_options, SslOpts0}]),
             AlpnOpts = hackney_ssl:alpn_opts(ConnectOpts),
             FinalSslOpts = hackney_util:merge_opts(MergedSslOpts, AlpnOpts),
             TransportOpts ++ [{ssl_options, FinalSslOpts}];
diff --git a/test/certs/ca.key b/test/certs/ca.key
new file mode 100644
index 00000000..383274cc
--- /dev/null
+++ b/test/certs/ca.key
@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+OiqVmZH4pUASQ0q1N8CMrSCu1Y7MZzLaUuLdL8GwL0NGZMBMSimTt7pfZDDeDda4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+-----END PRIVATE KEY-----
diff --git a/test/certs/ca.pem b/test/certs/ca.pem
new file mode 100644
index 00000000..372ccd97
--- /dev/null
+++ b/test/certs/ca.pem
@@ -0,0 +1,19 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/test/certs/server.key b/test/certs/server.key
new file mode 100644
index 00000000..b8322741
--- /dev/null
+++ b/test/certs/server.key
@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/test/certs/server.pem b/test/certs/server.pem
new file mode 100644
index 00000000..11233cdb
--- /dev/null
+++ b/test/certs/server.pem
@@ -0,0 +1,19 @@
+-----BEGIN CERTIFICATE-----
+MIIDEjCCAfqgAwIBAgIUeHOpIj5w7HfcnQw9T0ShnnZ3BjMwDQYJKoZIhvcNAQEL
+BQAwEjEQMA4GA1UEAwwHVGVzdCBDQTAeFw0yNjAzMTgwNzI3NDFaFw0zNjAzMTUw
+NzI3NDFaMBQxEjAQBgNVBAMMCWxvY2FsaG9zdDCCASIwDQYJKoZIhvcNAQEBBQAD
+ggEPADCCAQoCggEBAKhBFcWGxc/AhMnG9embpKHEogTUGpIKqhpU/JykQc8SvRLf
+FNeBN+nnde/SnYvrlu5wXZifj7XCid+oCHv3qmj/yNIj4XOiHnW0ezk5O8QZwvao
+dQUFe92mV5C5/gx4xTei4PHXMyteO7AO8J3DMKQ6Pp8Da/v7gE99ABMyiw7Le9tM
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++aNY56WXLW/xakKfmmyN++6gmeK0DhRdzd1rB1inf/Ssv78FZNtcMOrE3tMTkOxM
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+EYcEfwAAAYIJbG9jYWxob3N0MB0GA1UdDgQWBBQGilSdZDqBe3dZwUVJU+dZSwWF
+ZTAfBgNVHSMEGDAWgBTcWObZ/TNAq4tQqy34nNCttoc5FDANBgkqhkiG9w0BAQsF
+AAOCAQEALQzkn2Ggt2UhtqpLDMaYwY3h5+beqOVeZ8MYp+IOeJWNfDF072TE6pYH
+xiZYfJ+RdZePe7VqnQJEQsMMJ/6p5VEGSCNN0Zryz4by3Vu/JA3RX6JqRq55Al9I
+1CPwn2Ii+dE8CJYRXG63tqqYzchmPVwfing7/YpT8D7zUpRmsd9oU8PTlpnxonvc
+SmvZEBTf8PVEm6HlO/nPxOi0MvN8AkQ8EBH23qDWPsiAd6LN+nySVnukAPRlt+8Q
+ZTM6KneidFluqTzbacnw/9njlH7fyQktsUDQh3wzQ6+x10PjfFa25Vi1L+kRvk7x
+e3h+4kGHJQpRtEBQ3NoeaS0KccGahg==
+-----END CERTIFICATE-----
diff --git a/test/hackney_cacertfile_bug_test.erl b/test/hackney_cacertfile_bug_test.erl
new file mode 100644
index 00000000..dceec205
--- /dev/null
+++ b/test/hackney_cacertfile_bug_test.erl
@@ -0,0 +1,59 @@
+%%% Test that cacertfile option is respected when making HTTPS requests.
+%%%
+%%% Currently fails because hackney_conn.erl bypasses hackney_ssl:ssl_opts/2
+%%% and calls hackney_ssl:check_hostname_opts/1 directly, which always sets
+%%% {cacerts, certifi:cacerts()}. Erlang SSL then ignores cacertfile.
+
+-module(hackney_cacertfile_bug_test).
+-include_lib("eunit/include/eunit.hrl").
+
+-define(HTTPS_PORT, 8126).
+
+cacertfile_test_() ->
+    {setup,
+     fun setup/0,
+     fun teardown/1,
+     [
+      {"cacertfile respected in ssl_opts/2", fun test_ssl_opts_handles_cacertfile/0},
+      {"cacertfile respected in request", fun test_request_with_cacertfile/0}
+     ]}.
+
+setup() ->
+    error_logger:tty(false),
+    {ok, _} = application:ensure_all_started(cowboy),
+    {ok, _} = application:ensure_all_started(hackney),
+
+    CertDir = cert_dir(),
+    CertFile = filename:join(CertDir, "server.pem"),
+    KeyFile = filename:join(CertDir, "server.key"),
+
+    Dispatch = cowboy_router:compile([{'_', [{"/[...]", test_http_resource, []}]}]),
+    {ok, _} = cowboy:start_tls(cacertfile_test_server,
+                                [{certfile, CertFile},
+                                 {keyfile, KeyFile},
+                                 {port, ?HTTPS_PORT}],
+                                #{env => #{dispatch => Dispatch}}),
+    ok.
+
+teardown(_) ->
+    cowboy:stop_listener(cacertfile_test_server),
+    application:stop(cowboy),
+    application:stop(hackney),
+    error_logger:tty(true),
+    ok.
+
+test_ssl_opts_handles_cacertfile() ->
+    CACertFile = filename:join(cert_dir(), "ca.pem"),
+    Options = [{ssl_options, [{cacertfile, CACertFile}]}],
+    SslOpts = hackney_ssl:ssl_opts("localhost", Options),
+    ?assert(lists:keymember(cacertfile, 1, SslOpts)),
+    ?assertNot(lists:keymember(cacerts, 1, SslOpts)).
+
+test_request_with_cacertfile() ->
+    CACertFile = filename:join(cert_dir(), "ca.pem"),
+    Url = "https://localhost:" ++ integer_to_list(?HTTPS_PORT) ++ "/get",
+    Opts = [{ssl_options, [{cacertfile, CACertFile}]}, {pool, false}],
+    {ok, 200, _, _} = hackney:request(get, Url, [], <<>>, Opts).
+
+cert_dir() ->
+    filename:join([filename:dirname(code:which(?MODULE)), "..", "test", "certs"]).