diff --git a/sonic_platform_base/sonic_xcvr/api/public/c_cmis.py b/sonic_platform_base/sonic_xcvr/api/public/c_cmis.py
index 65acbc274..aa8a6cbff 100644
--- a/sonic_platform_base/sonic_xcvr/api/public/c_cmis.py
+++ b/sonic_platform_base/sonic_xcvr/api/public/c_cmis.py
@@ -88,9 +88,15 @@ def get_laser_config_freq(self):
         '''
         freq_grid = self.get_freq_grid()
         channel = self.xcvr_eeprom.read(consts.LASER_CONFIG_CHANNEL)
+        # OIF-CMIS 5.3 Table 8-66: 75GHz is 193.1 + n x 0.025 THz, but 150GHz
+        # is 193.1 + (n+3) x 0.025 THz - the two grids are not interchangeable.
         if freq_grid == 75:
-            config_freq = 193100 + channel * freq_grid/3
+            config_freq = 193100 + channel * 25
+        elif freq_grid == 150:
+            config_freq = 193100 + (channel + 3) * 25
         else:
+            # All other grids (100/50/25/12.5/6.25/3.125GHz) use a plain
+            # 193.1 + n x grid formula with no additive offset.
             config_freq = 193100 + channel * freq_grid
         return config_freq
 
@@ -154,7 +160,7 @@ def set_laser_freq(self, freq, grid):
         '''
         This function sets the laser frequency. Unit in GHz
         ZR application will not support fine tuning of the laser
-        SONiC will only support 75 GHz and 100GHz frequency grids
+        SONiC will support 75 GHz, 100GHz and 150GHz frequency grids
         Return True if the provision succeeds, False if it fails
         '''
         grid_supported, low_ch_num, hi_ch_num, _, _ = self.get_supported_freq_config()
@@ -169,6 +175,13 @@ def set_laser_freq(self, freq, grid):
             assert grid_supported_100GHz
             freq_grid = 0x50
             channel_number = int(round((freq - 193100)/100))
+        elif grid == 150:
+            freq_grid = 0x80
+            # OIF-CMIS 5.3 Table 8-66: Frequency (THz) = 193.1 + (n+3) x 0.025,
+            # so n = (freq - 193100) / 25 - 3, and n (not n+3) must be a
+            # multiple of 6.
+            channel_number = int(round((freq - 193100)/25)) - 3
+            assert channel_number % 6 == 0
         else:
             return False
         self.xcvr_eeprom.write(consts.GRID_SPACING, freq_grid)
diff --git a/tests/sonic_xcvr/test_ccmis.py b/tests/sonic_xcvr/test_ccmis.py
index 53a996c65..ba8cd0482 100644
--- a/tests/sonic_xcvr/test_ccmis.py
+++ b/tests/sonic_xcvr/test_ccmis.py
@@ -5,6 +5,7 @@
 from sonic_platform_base.sonic_xcvr.mem_maps.public.cmis.c_cmis import CCmisMemMap
 from sonic_platform_base.sonic_xcvr.xcvr_eeprom import XcvrEeprom
 from sonic_platform_base.sonic_xcvr.codes.public.cmis import CmisCodes
+from sonic_platform_base.sonic_xcvr.fields import consts
 
 
 class TestCCmis(object):
@@ -39,6 +40,11 @@ def test_get_freq_grid(self, mock_response, expected):
         (75, 12, 193400),
         (75, -30, 192350),
         (100, 10, 194100),
+        # OIF-CMIS 5.3 Table 8-66: 150GHz grid is 193.1 + (n+3) x 0.025 THz,
+        # a +75GHz offset from the naive 193.1 + n x 0.025 used for 75GHz.
+        (150, 12, 193475),
+        (150, 0, 193175),
+        (150, -3, 193100),
     ])
     def test_get_laser_config_freq(self, mock_response1, mock_response2, expected):
         self.api.get_freq_grid = MagicMock()
@@ -98,6 +104,10 @@ def test_get_supported_freq_config(self, mock_response, expected):
     @pytest.mark.parametrize("input_param, mock_response",[
         ((193100,75), (0xff, -72, 120, 191300, 196100)),
         ((195950,100), (0xff, -72, 120, 191300, 196100)),
+        # 193475 is a valid 150GHz-grid point post-offset-fix (n=12); see
+        # test_set_laser_freq_150ghz_channel_offset for the exact channel
+        # number written.
+        ((193475,150), (0xff, -72, 120, 191300, 196100)),
     ])
     def test_set_laser_freq(self, input_param, mock_response):
         self.api.is_flat_memory = MagicMock()
@@ -108,6 +118,18 @@ def test_set_laser_freq(self, input_param, mock_response):
         self.api.get_supported_freq_config.return_value = mock_response
         self.api.set_laser_freq(input_param[0], input_param[1])
 
+    def test_set_laser_freq_150ghz_channel_offset(self):
+        # OIF-CMIS 5.3 Table 8-66: Frequency = 193.1 + (n+3) x 0.025 THz for
+        # the 150GHz grid, so the channel number written must be 3 less than
+        # the naive (freq-193100)/25 used for the 75GHz grid.
+        self.api.is_flat_memory = MagicMock(return_value=False)
+        self.api.get_lpmode_support = MagicMock(return_value=False)
+        self.api.get_supported_freq_config = MagicMock(
+            return_value=(0xff, -72, 120, 191300, 196100))
+        self.api.xcvr_eeprom.write = MagicMock(return_value=True)
+        self.api.set_laser_freq(193475, 150)
+        self.api.xcvr_eeprom.write.assert_any_call(consts.LASER_CONFIG_CHANNEL, 12)
+
     @pytest.mark.parametrize("input_param, mock_response",[
         (-10, (-14, -9)),
         (-8, (-12, -8)),