diff --git a/interfaces/matlab/toolbox/@Interface/setCoverages.m b/interfaces/matlab/toolbox/@Interface/setCoverages.m
index d2985684d..7b45acbb1 100644
--- a/interfaces/matlab/toolbox/@Interface/setCoverages.m
+++ b/interfaces/matlab/toolbox/@Interface/setCoverages.m
@@ -1,18 +1,31 @@
-function setCoverages(s, cov)
+function setCoverages(s, cov, norm)
 % SETCOVERAGES  Set surface coverages of the species on an interface.
-% setCoverages(s, cov)
+% setCoverages(s, cov, norm)
 % :param s:
 %      Instance of class :mat:func:`Interface`
 % :param cov:
 %      Coverage of the species. ``cov`` can be either a vector of
 %      length ``n_surf_species``, or a string in the format
 %      ``'Species:Coverage, Species:Coverage'``
+% :param norm:
+%      Optional flag that denotes whether or not to normalize the species
+%      coverages. ``norm`` is either of the two strings ``'nonorm'``` or
+%      ``'norm'``. If left unset, the default is `norm`. This only works if
+%      ``s`` is a vector, not a string. Since unnormalized coverages can lead to
+%      unphysical results, ``'nonorm'`` should be used only in rare cases, such
+%      as computing partial derivatives with respect to a species coverage.
 %
 
+if nargin == 3 && strcmp(norm,'nonorm')
+    norm_flag = 0;
+else
+    norm_flag  = 1;
+end
+
 if isa(cov, 'double')
     sz = length(cov);
     if sz == nSpecies(s)
-        surfmethods(thermo_hndl(s), 3, cov);
+        surfmethods(thermo_hndl(s), 3, cov, norm_flag);
     else
         error('wrong size for coverage array');
     end
diff --git a/src/clib/ctsurf.cpp b/src/clib/ctsurf.cpp
index d3d6a82bc..eb76ef89d 100644
--- a/src/clib/ctsurf.cpp
+++ b/src/clib/ctsurf.cpp
@@ -35,10 +35,14 @@ extern "C" {
         }
     }
 
-    int surf_setcoverages(int i, double* c)
+    int surf_setcoverages(int i, double* c, int norm)
     {
         try {
-            ThermoCabinet::get<SurfPhase>(i).setCoverages(c);
+            if(norm){
+                ThermoCabinet::get<SurfPhase>(i).setCoverages(c);
+            } else {
+                ThermoCabinet::get<SurfPhase>(i).setCoveragesNoNorm(c);
+            }
             return 0;
         } catch (...) {
             return handleAllExceptions(-1, ERR);
diff --git a/src/clib/ctsurf.h b/src/clib/ctsurf.h
index 377228bb9..bb1298b80 100644
--- a/src/clib/ctsurf.h
+++ b/src/clib/ctsurf.h
@@ -8,7 +8,7 @@
 #include "cantera/base/config.h"
 
 extern "C" {
-    CANTERA_CAPI int surf_setcoverages(int i, double* c);
+    CANTERA_CAPI int surf_setcoverages(int i, double* c, int norm);
     CANTERA_CAPI int surf_getcoverages(int i, double* c);
     CANTERA_CAPI int surf_setconcentrations(int i, double* c);
     CANTERA_CAPI int surf_getconcentrations(int i, double* c);
diff --git a/src/matlab/surfmethods.cpp b/src/matlab/surfmethods.cpp
index 15d7b29d4..e4e71c393 100644
--- a/src/matlab/surfmethods.cpp
+++ b/src/matlab/surfmethods.cpp
@@ -14,6 +14,7 @@ void surfmethods(int nlhs, mxArray* plhs[],
     double vv;
     int job = getInt(prhs[2]);
     int iok = 0;
+    int norm = 0;
     double* ptr;
     char* str;
     size_t nsp, n, m;
@@ -28,13 +29,14 @@ void surfmethods(int nlhs, mxArray* plhs[],
             iok = surf_setsitedensity(surf, vv);
             break;
         case 3:
-            checkNArgs(4, nrhs);
+            checkNArgs(5, nrhs);
             ptr = mxGetPr(prhs[3]);
             m = mxGetM(prhs[3]);
             n = mxGetN(prhs[3]);
             nsp = phase_nSpecies(surf);
+            norm = getInt(prhs[4]);
             if ((m == nsp && n == 1) || (m == 1 && n == nsp)) {
-                iok = surf_setcoverages(surf, ptr);
+                iok = surf_setcoverages(surf, ptr, norm);
             } else {
                 mexErrMsgTxt("wrong array size for coverages");
             }