diff --git a/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
index 587c6b6e10ddb..662331558c121 100644
--- a/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stdlib_h.pass.cpp
@@ -8,6 +8,11 @@
 
 // test <stdlib.h>
 
+// mblen was added in Android API 26.
+// TODO: Switch from UNSUPPORTED to XFAIL once the Android CI Docker sysroot is
+// updated.
+// UNSUPPORTED: LIBCXX-ANDROID-FIXME && target={{.+}}-android{{(eabi)?(21|22|23|24|25)}}
+
 #include <stdlib.h>
 #include <cassert>
 #include <type_traits>
diff --git a/libcxx/test/std/depr/depr.c.headers/wctype_h.compile.pass.cpp b/libcxx/test/std/depr/depr.c.headers/wctype_h.compile.pass.cpp
index 35b294532b2bd..4e2fb319336f1 100644
--- a/libcxx/test/std/depr/depr.c.headers/wctype_h.compile.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/wctype_h.compile.pass.cpp
@@ -8,6 +8,11 @@
 
 // UNSUPPORTED: no-wide-characters
 
+// towctrans and wctrans were added in Android API 26.
+// TODO: Switch from UNSUPPORTED to XFAIL once the Android CI Docker sysroot is
+// updated.
+// UNSUPPORTED: LIBCXX-ANDROID-FIXME && target={{.+}}-android{{(eabi)?(21|22|23|24|25)}}
+
 // <wctype.h>
 
 #include <wctype.h>
diff --git a/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp b/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
index a1f7e1143a1e9..9d3e6d892daf0 100644
--- a/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/cstdlib.pass.cpp
@@ -8,6 +8,11 @@
 
 // test <cstdlib>
 
+// mblen was added in Android API 26.
+// TODO: Switch from UNSUPPORTED to XFAIL once the Android CI Docker sysroot is
+// updated.
+// UNSUPPORTED: LIBCXX-ANDROID-FIXME && target={{.+}}-android{{(eabi)?(21|22|23|24|25)}}
+
 #include <cstdlib>
 #include <cassert>
 #include <type_traits>
diff --git a/libcxx/test/std/strings/c.strings/cwctype.pass.cpp b/libcxx/test/std/strings/c.strings/cwctype.pass.cpp
index 5bc2531d6f6ac..0deabf51ed59c 100644
--- a/libcxx/test/std/strings/c.strings/cwctype.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cwctype.pass.cpp
@@ -10,6 +10,11 @@
 
 // UNSUPPORTED: no-wide-characters
 
+// towctrans and wctrans were added in Android API 26.
+// TODO: Switch from UNSUPPORTED to XFAIL once the Android CI Docker sysroot is
+// updated.
+// UNSUPPORTED: LIBCXX-ANDROID-FIXME && target={{.+}}-android{{(eabi)?(21|22|23|24|25)}}
+
 #include <cwctype>
 #include <type_traits>