diff --git a/Makefile b/Makefile
index bcc40c17..5a76ddda 100644
--- a/Makefile
+++ b/Makefile
@@ -81,8 +81,8 @@ CLEAN_TARGETS = $(foreach B,$(BUILD_ITEMS),clean_$(B))
 
 # For test suitse
 export QPDF_BIN = $(abspath qpdf/$(OUTPUT_DIR)/qpdf)
-export SKIP_TEST_COMPARE_IMAGES
-export LARGE_FILE_TEST_PATH
+export QPDF_SKIP_TEST_COMPARE_IMAGES
+export QPDF_LARGE_FILE_TEST_PATH
 
 clean:: $(CLEAN_TARGETS)
 
diff --git a/autoconf.mk.in b/autoconf.mk.in
index cf7fa10f..630ba91e 100644
--- a/autoconf.mk.in
+++ b/autoconf.mk.in
@@ -32,10 +32,10 @@ XMLLINT=@XMLLINT@
 BUILD_HTML=@BUILD_HTML@
 BUILD_PDF=@BUILD_PDF@
 VALIDATE_DOC=@VALIDATE_DOC@
-SKIP_TEST_COMPARE_IMAGES=@SKIP_TEST_COMPARE_IMAGES@
+QPDF_SKIP_TEST_COMPARE_IMAGES=@QPDF_SKIP_TEST_COMPARE_IMAGES@
 BUILDRULES=@BUILDRULES@
 HAVE_LD_VERSION_SCRIPT=@HAVE_LD_VERSION_SCRIPT@
 WINDOWS_WORDSIZE=@WINDOWS_WORDSIZE@
 SHOW_FAILED_TEST_OUTPUT=@SHOW_FAILED_TEST_OUTPUT@
 # Allow environment variable to override
-LARGE_FILE_TEST_PATH?=@LARGE_FILE_TEST_PATH@
+QPDF_LARGE_FILE_TEST_PATH?=@QPDF_LARGE_FILE_TEST_PATH@
diff --git a/configure.ac b/configure.ac
index 26aaf265..6423284d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -54,13 +54,13 @@ if test "$BUILD_INTERNAL_LIBS" = "0"; then
    AC_SEARCH_LIBS(pcre_compile,pcre,,[MISSING_PCRE=1; MISSING_ANY=1])
 fi
 
-LARGE_FILE_TEST_PATH=
-AC_SUBST(LARGE_FILE_TEST_PATH)
+QPDF_LARGE_FILE_TEST_PATH=
+AC_SUBST(QPDF_LARGE_FILE_TEST_PATH)
 AC_ARG_WITH(large-file-test-path,
    AS_HELP_STRING([--with-large-file-test-path=path],
-		  [To enable testing of files > 4GB, give the path to a directory with at least 11 GB free.  The test suite will write temporary files to this directory.  Alternatively, just set the LARGE_FILE_TEST_PATH environment variable to the path before running the test suite.]),
-   [LARGE_FILE_TEST_PATH=$withval],
-   [LARGE_FILE_TEST_PATH=])
+		  [To enable testing of files > 4GB, give the path to a directory with at least 11 GB free.  The test suite will write temporary files to this directory.  Alternatively, just set the QPDF_LARGE_FILE_TEST_PATH environment variable to the path before running the test suite.]),
+   [QPDF_LARGE_FILE_TEST_PATH=$withval],
+   [QPDF_LARGE_FILE_TEST_PATH=])
 
 AC_SYS_LARGEFILE
 AC_FUNC_FSEEKO
@@ -210,16 +210,16 @@ if test "$BUILDRULES" != "msvc"; then
    fi
 fi
 
-AC_SUBST(SKIP_TEST_COMPARE_IMAGES)
+AC_SUBST(QPDF_SKIP_TEST_COMPARE_IMAGES)
 AC_ARG_ENABLE(test-compare-images,
    AS_HELP_STRING([--enable-test-compare-images],
 		  [whether to compare images in test suite; disabled by default, enabling requires ghostscript and tiffcmp to be available]),
    [if test "$enableval" = "no"; then
-      SKIP_TEST_COMPARE_IMAGES=1
+      QPDF_SKIP_TEST_COMPARE_IMAGES=1
     else
-      SKIP_TEST_COMPARE_IMAGES=0
+      QPDF_SKIP_TEST_COMPARE_IMAGES=0
     fi],
-   [SKIP_TEST_COMPARE_IMAGES=1])
+   [QPDF_SKIP_TEST_COMPARE_IMAGES=1])
 
 AC_SUBST(SHOW_FAILED_TEST_OUTPUT)
 AC_ARG_ENABLE(show-failed-test-output,
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index d9cd6f06..8cdc82a7 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -16,12 +16,12 @@ cleanup();
 my $td = new TestDriver('qpdf');
 
 my $compare_images = 1;
-if ((exists $ENV{'SKIP_TEST_COMPARE_IMAGES'}) &&
-    ($ENV{'SKIP_TEST_COMPARE_IMAGES'} eq '1'))
+if ((exists $ENV{'QPDF_SKIP_TEST_COMPARE_IMAGES'}) &&
+    ($ENV{'QPDF_SKIP_TEST_COMPARE_IMAGES'} eq '1'))
 {
     $compare_images = 0;
 }
-my $large_file_test_path = $ENV{'LARGE_FILE_TEST_PATH'} || undef;
+my $large_file_test_path = $ENV{'QPDF_LARGE_FILE_TEST_PATH'} || undef;
 
 my $have_acroread = 0;