diff --git a/tests/.gitignore b/tests/.gitignore
index 15fce68..b85d66a 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -13,6 +13,8 @@
 data_files/ctr_drbg_seed
 data_files/entropy_seed
 
+include/alt-extra/psa/crypto_platform_alt.h
+include/alt-extra/psa/crypto_struct_alt.h
 include/test/instrument_record_status.h
 
 src/*.o
diff --git a/tests/Makefile b/tests/Makefile
index c9283c9..26947f4 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -219,6 +219,7 @@
 	rm -rf $(BINARIES) *.c *.datax
 	rm -f src/*.o src/drivers/*.o src/libmbed*
 	rm -f include/test/instrument_record_status.h
+	rm -f include/alt-extra/*/*_alt.h
 	rm -rf libtestdriver1
 	rm -f ../library/libtestdriver1.a
 else
@@ -244,6 +245,10 @@
 
 test: check
 
+# Generate variants of some headers for testing
+include/alt-extra/%_alt.h: ../include/%.h
+	perl -p -e 's/^(# *(define|ifndef) +\w+_)H\b/$${1}ALT_H/' $< >$@
+
 # Generate test library
 
 # Perl code that is executed to transform each original line from a library
diff --git a/tests/include/alt-extra/psa/crypto.h b/tests/include/alt-extra/psa/crypto.h
new file mode 100644
index 0000000..005f3ae
--- /dev/null
+++ b/tests/include/alt-extra/psa/crypto.h
@@ -0,0 +1,7 @@
+/* The goal of the include/alt-extra directory is to test what happens
+ * if certain files come _after_ the normal include directory.
+ * Make sure that if the alt-extra directory comes before the normal
+ * directory (so we wouldn't be achieving our test objective), the build
+ * will fail.
+ */
+#error "The normal include directory must come first in the include path"
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 7d91fa2..a851d0e 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -3258,6 +3258,27 @@
     rm -f psa_test_config.h psa_user_config.h
 }
 
+component_build_psa_alt_headers () {
+    msg "build: make with PSA alt headers" # ~20s
+
+    # Generate alternative versions of the substitutable headers with the
+    # same content except different include guards.
+    make -C tests include/alt-extra/psa/crypto_platform_alt.h include/alt-extra/psa/crypto_struct_alt.h
+
+    # Build the library and some programs.
+    # Don't build the fuzzers to avoid having to go through hoops to set
+    # a correct include path for programs/fuzz/Makefile.
+    make CFLAGS="-I ../tests/include/alt-extra -DMBEDTLS_PSA_CRYPTO_PLATFORM_FILE='\"psa/crypto_platform_alt.h\"' -DMBEDTLS_PSA_CRYPTO_STRUCT_FILE='\"psa/crypto_struct_alt.h\"'" lib
+    make -C programs -o fuzz CFLAGS="-I ../tests/include/alt-extra -DMBEDTLS_PSA_CRYPTO_PLATFORM_FILE='\"psa/crypto_platform_alt.h\"' -DMBEDTLS_PSA_CRYPTO_STRUCT_FILE='\"psa/crypto_struct_alt.h\"'"
+
+    # Check that we're getting the alternative include guards and not the
+    # original include guards.
+    programs/test/query_included_headers | grep -x PSA_CRYPTO_PLATFORM_ALT_H
+    programs/test/query_included_headers | grep -x PSA_CRYPTO_STRUCT_ALT_H
+    programs/test/query_included_headers | not grep -x PSA_CRYPTO_PLATFORM_H
+    programs/test/query_included_headers | not grep -x PSA_CRYPTO_STRUCT_H
+}
+
 component_test_m32_o0 () {
     # Build without optimization, so as to use portable C code (in a 32-bit
     # build) and not the i386-specific inline assembly.