diff --git a/keyboards/spiderisland/split78/config.h b/keyboards/spiderisland/split78/config.h
new file mode 100644
index 0000000000..a7ec160faf
--- /dev/null
+++ b/keyboards/spiderisland/split78/config.h
@@ -0,0 +1,35 @@
+/*
+Copyright 2020 unrelenting.technology
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include "config_common.h"
+
+/* USB Device descriptor parameter */
+#define VENDOR_ID    0xFEED
+#define PRODUCT_ID   0xF4E4
+#define DEVICE_VER   0x0001
+#define MANUFACTURER SpiderIsland
+#define PRODUCT      Split 78-key
+
+/* key matrix size */
+#define MATRIX_ROWS 8
+#define MATRIX_COLS 14
+
+#define BACKLIGHT_PIN D4
+#define BACKLIGHT_LEVELS 3
+#define BACKLIGHT_BREATHING
diff --git a/keyboards/spiderisland/split78/info.json b/keyboards/spiderisland/split78/info.json
new file mode 100644
index 0000000000..7a96efe762
--- /dev/null
+++ b/keyboards/spiderisland/split78/info.json
@@ -0,0 +1,94 @@
+{
+    "keyboard_name": "Spider Island 78-key split",
+    "url": "",
+    "maintainer": "qmk",
+    "width": 16,
+    "height": 6.25,
+    "layouts": {
+        "LAYOUT": {
+            "layout": [
+                {"x": 0, "y": 0},
+                {"x": 2, "y": 0},
+                {"x": 3, "y": 0},
+                {"x": 4, "y": 0},
+                {"x": 5, "y": 0},
+                {"x": 6.5, "y": 0},
+                {"x": 8.5, "y": 0},
+                {"x": 9.5, "y": 0},
+                {"x": 10.5, "y": 0},
+                {"x": 12, "y": 0},
+                {"x": 13, "y": 0},
+                {"x": 14, "y": 0},
+                {"x": 15, "y": 0},
+                {"x": 0, "y": 1.25},
+                {"x": 1, "y": 1.25},
+                {"x": 2, "y": 1.25},
+                {"x": 3, "y": 1.25},
+                {"x": 4, "y": 1.25},
+                {"x": 5, "y": 1.25},
+                {"x": 6, "y": 1.25},
+                {"x": 8, "y": 1.25},
+                {"x": 9, "y": 1.25},
+                {"x": 10, "y": 1.25},
+                {"x": 11, "y": 1.25},
+                {"x": 12, "y": 1.25},
+                {"x": 13, "y": 1.25},
+                {"x": 14, "y": 1.25, "w": 2},
+                {"x": 0, "y": 2.25, "w": 1.5},
+                {"x": 1.5, "y": 2.25},
+                {"x": 2.5, "y": 2.25},
+                {"x": 3.5, "y": 2.25},
+                {"x": 4.5, "y": 2.25},
+                {"x": 5.5, "y": 2.25},
+                {"x": 7.5, "y": 2.25},
+                {"x": 8.5, "y": 2.25},
+                {"x": 9.5, "y": 2.25},
+                {"x": 10.5, "y": 2.25},
+                {"x": 11.5, "y": 2.25},
+                {"x": 12.5, "y": 2.25},
+                {"x": 13.5, "y": 2.25},
+                {"x": 14.5, "y": 2.25, "w": 1.5},
+
+                {"x": 0, "y": 3.25, "w": 1.75},
+                {"x": 1.75, "y": 3.25},
+                {"x": 2.75, "y": 3.25},
+                {"x": 3.75, "y": 3.25},
+                {"x": 4.75, "y": 3.25},
+                {"x": 5.75, "y": 3.25},
+                {"x": 7.75, "y": 3.25},
+                {"x": 8.75, "y": 3.25},
+                {"x": 9.75, "y": 3.25},
+                {"x": 10.75, "y": 3.25},
+                {"x": 11.75, "y": 3.25},
+                {"x": 12.75, "y": 3.25},
+                {"x": 13.75, "y": 3.25, "w": 2.25},
+
+                {"x": 0, "y": 4.25, "w": 2.25},
+                {"x": 2.25, "y": 4.25},
+                {"x": 3.25, "y": 4.25},
+                {"x": 4.25, "y": 4.25},
+                {"x": 5.25, "y": 4.25},
+                {"x": 6.25, "y": 4.25},
+                {"x": 8.25, "y": 4.25},
+                {"x": 9.25, "y": 4.25},
+                {"x": 10.25, "y": 4.25},
+                {"x": 11.25, "y": 4.25},
+                {"x": 12.25, "y": 4.25, "w": 1.75},
+                {"x": 14, "y": 4.25},
+                {"x": 15, "y": 4.25},
+
+                {"x": 0, "y": 5.25, "w": 1.25},
+                {"x": 1.25, "y": 5.25, "w": 1.25},
+                {"x": 2.5, "y": 5.25, "w": 1.25},
+                {"x": 3.75, "y": 5.25, "w": 1.25},
+                {"x": 5, "y": 5.25, "w": 2.25},
+                {"x": 8.25, "y": 5.25, "w": 2.25},
+                {"x": 10.5, "y": 5.25, "w": 1.25},
+                {"x": 11.75, "y": 5.25, "w": 1.25},
+                {"x": 13, "y": 5.25},
+                {"x": 14, "y": 5.25},
+                {"x": 15, "y": 5.25}
+            ]
+        }
+    }
+}
diff --git a/keyboards/spiderisland/split78/keymaps/default/keymap.c b/keyboards/spiderisland/split78/keymaps/default/keymap.c
new file mode 100644
index 0000000000..761648d958
--- /dev/null
+++ b/keyboards/spiderisland/split78/keymaps/default/keymap.c
@@ -0,0 +1,41 @@
+/* Copyright 2020 unrelenting.technology
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include QMK_KEYBOARD_H
+
+// Defines names for use in layer keycodes and the keymap
+enum layer_names {
+    _BASE,
+    _FN
+};
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+    [_BASE] = LAYOUT(
+        KC_GESC,          KC_F1,   KC_F2,   KC_F3,   KC_F4,   KC_F5,   KC_F6,   KC_F7,   KC_F8,   KC_F9,   KC_F10,  KC_F11,  KC_F12,
+        KC_GRV,  KC_1,    KC_2,    KC_3,    KC_4,    KC_5,    KC_6,    KC_7,    KC_8,    KC_9,    KC_0,    KC_MINS, KC_EQL,  KC_BSPC,
+        KC_TAB,  KC_Q,    KC_W,    KC_E,    KC_R,    KC_T,    KC_Y,    KC_U,    KC_I,    KC_O,    KC_P,    KC_LBRC, KC_RBRC, KC_BSLS,
+        KC_CAPS, KC_A,    KC_S,    KC_D,    KC_F,    KC_G,    KC_H,    KC_J,    KC_K,    KC_L,    KC_QUOT, KC_SCLN,          KC_ENT,
+        KC_LSFT,          KC_Z,    KC_X,    KC_C,    KC_V,    KC_B,    KC_N,    KC_M,    KC_COMM, KC_DOT,  KC_RSFT, KC_UP,   KC_SLSH,
+        KC_LCTL, KC_LGUI, KC_LALT, TT(_FN),          KC_SPC,           KC_SPC,           KC_RALT, KC_RCTL, KC_LEFT, KC_DOWN, KC_RGHT
+    ),
+    [_FN] = LAYOUT(
+        RESET,            KC_F13,  KC_F14,  KC_F15,  KC_F16,  KC_F17,  KC_F18,  KC_F19,  KC_F20,  KC_F21,  KC_F22,  KC_F23,  KC_F24,
+        XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, BL_DEC,  BL_INC,  KC_DEL,
+        KC_NLCK, XXXXXXX, KC_UP,   XXXXXXX, XXXXXXX, XXXXXXX, KC_P7,   KC_P8,   KC_P9,   XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX,
+        BL_TOGG, KC_LEFT, KC_DOWN, KC_RGHT, XXXXXXX, XXXXXXX, KC_P4,   KC_P5,   KC_P6,   XXXXXXX, XXXXXXX, XXXXXXX,          XXXXXXX,
+        KC_SLCK,          XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX, KC_P1,   KC_P2,   KC_P3,   XXXXXXX, KC_SLSH, KC_PGUP, XXXXXXX,
+        XXXXXXX, XXXXXXX, XXXXXXX, XXXXXXX,          XXXXXXX,          KC_P0,            KC_PDOT, KC_PENT, KC_HOME, KC_PGDN, KC_END
+    )
+};
diff --git a/keyboards/spiderisland/split78/matrix.c b/keyboards/spiderisland/split78/matrix.c
new file mode 100644
index 0000000000..b5c7028fdf
--- /dev/null
+++ b/keyboards/spiderisland/split78/matrix.c
@@ -0,0 +1,155 @@
+/*
+Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <string.h>
+#include <stdio.h>
+#include "quantum.h"
+#include "i2c_master.h"
+#include "split78.h"
+
+#define RIGHT_HALF
+
+
+void matrix_set_row_status(uint8_t row);
+
+
+#if defined(RIGHT_HALF)
+#define I2C_TIMEOUT     10
+#define MCP23018_TWI_ADDRESS 0b0100000
+#define TW_READ        1
+#define TW_WRITE    0
+#define TWI_ADDR_WRITE ( (MCP23018_TWI_ADDRESS<<1) | TW_WRITE )
+#define TWI_ADDR_READ  ( (MCP23018_TWI_ADDRESS<<1) | TW_READ  )
+#define IODIRA 0x00  // i/o direction register
+#define IODIRB 0x01
+#define IODIRA 0x00  // i/o direction register
+#define IODIRB 0x01
+#define GPPUA  0x0C  // GPIO pull-up resistor register
+#define GPPUB  0x0D
+#define GPIOA  0x12  // general purpose i/o port register (write modifies OLAT)
+#define GPIOB  0x13
+#define OLATA  0x14  // output latch register
+#define OLATB  0x15
+#define MCP_ROWS_START    8
+
+static uint8_t mcp23018_init(void) {
+    uint8_t ret;
+    uint8_t data[3];
+    // set pin direction
+    // - unused  : input  : 1
+    // - input   : input  : 1
+    // - driving : output : 0
+    data[0] = IODIRA;
+    data[1] = 0b00000000;  // IODIRA
+    data[2] = (0b11111111);  // IODIRB
+
+    ret = i2c_transmit(TWI_ADDR_WRITE, (uint8_t *)data, 3, I2C_TIMEOUT);
+    if (ret) goto out;  // make sure we got an ACK
+
+    // set pull-up
+    // - unused  : on  : 1
+    // - input   : on  : 1
+    // - driving : off : 0
+    data[0] = GPPUA;
+    data[1] = 0b00000000;  // IODIRA
+    data[2] = (0b11111111);  // IODIRB
+
+    ret = i2c_transmit(TWI_ADDR_WRITE, (uint8_t *)data, 3, I2C_TIMEOUT);
+    if (ret) goto out;  // make sure we got an ACK
+
+    // set logical value (doesn't matter on inputs)
+    // - unused  : hi-Z : 1
+    // - input   : hi-Z : 1
+    // - driving : hi-Z : 1
+    data[0] = OLATA;
+    data[1] = 0b11111111;  // IODIRA
+    data[2] = (0b11111111);  // IODIRB
+
+    ret = i2c_transmit(TWI_ADDR_WRITE, (uint8_t *)data, 3, I2C_TIMEOUT);
+
+out:
+    return ret;
+}
+#endif
+
+void matrix_init_custom(void) {
+    // Set rows as output starting high
+    DDRB = 0xFF;
+    PORTB = 0xFF;
+
+    // Set columns as inputs with pull-up enabled
+    DDRA = 0x00;
+    PORTA = 0xFF;
+
+    // Initialize i2c communication
+    i2c_init();
+
+#if defined(RIGHT_HALF)
+    // Initialize the chip on the other half
+    mcp23018_init();
+#endif
+
+}
+
+bool matrix_scan_custom(matrix_row_t current_matrix[]) {
+    bool matrix_has_changed = false;
+
+    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+        // Store last value of row prior to reading
+        matrix_row_t last_row_value = current_matrix[row];
+
+        matrix_row_t cols = 0;
+	    // Select the row to scan
+        matrix_set_row_status(row);
+
+        matrix_io_delay();
+	    //Set the local row
+
+#if defined(RIGHT_HALF)
+		// Initialize to 0x7F in case I2C read fails,
+		// as 0x75 would be no keys pressed
+		uint8_t data = 0x7F;
+		// Receive the columns from right half
+		i2c_receive(TWI_ADDR_WRITE, &data, 1, I2C_TIMEOUT);
+#endif
+
+        cols |= ((~(PINA | 0x80)) & 0x7F);
+#if defined(RIGHT_HALF)
+		cols |= (((~(data | 0x80)) & 0x7F) << 7);
+#endif
+
+        current_matrix[row] = cols;
+        matrix_has_changed |= (last_row_value != current_matrix[row]);
+    }
+
+    return matrix_has_changed;
+}
+
+void matrix_set_row_status(uint8_t row) {
+#if defined(RIGHT_HALF)
+    uint8_t txdata[3];
+
+    //Set the remote row on port A
+    txdata[0] = (GPIOA);
+    txdata[1] = ( 0xFF & ~(1<<row) );
+    i2c_transmit(TWI_ADDR_WRITE, (uint8_t *)txdata, 2, I2C_TIMEOUT);
+#endif
+
+    //Set the local row on port B
+    DDRB = (1 << row);
+    PORTB = ~(1 << row);
+}
diff --git a/keyboards/spiderisland/split78/readme.md b/keyboards/spiderisland/split78/readme.md
new file mode 100644
index 0000000000..704ffcd263
--- /dev/null
+++ b/keyboards/spiderisland/split78/readme.md
@@ -0,0 +1,25 @@
+# SpiderIsland Split 78-key
+
+![Board Photo](https://i.imgur.com/N3DjdGql.jpg)  
+[Image Gallery](https://imgur.com/a/0AUY8Ng)
+
+The 78 key split keyboard from [SpiderIsland on AliExpress](https://a.aliexpress.com/_dVJsSpR).
+Out of the box it runs ps2avrGB firmware, like [`split75`](../../wheatfield/split75/README.md).
+It is mistakenly called "87 key" on the AliExpress title and "104 key" (?!) in the caption inside the photo.
+
+This port is based on the `split75` port which was mostly done by [Michael L. Walker](https://github.com/walkerstop).
+
+* Keyboard Maintainer: [unrelenting.technology](https://github.com/myfreeweb)
+* Hardware Availability: https://a.aliexpress.com/_dVJsSpR
+
+Make example for this keyboard (after setting up your build environment):
+
+    make spiderisland/split78:default
+
+Flashing example for this keyboard ([after setting up the bootloadHID flashing environment](https://docs.qmk.fm/#/flashing_bootloadhid))
+
+    make spiderisland/split78:default:flash
+
+**Reset Key**: Hold down the key located at the leftmost position in the top row, commonly programmed as Escape while plugging in the keyboard.
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
diff --git a/keyboards/spiderisland/split78/rules.mk b/keyboards/spiderisland/split78/rules.mk
new file mode 100644
index 0000000000..61015b97f5
--- /dev/null
+++ b/keyboards/spiderisland/split78/rules.mk
@@ -0,0 +1,24 @@
+# MCU name
+MCU = atmega32a
+
+# Bootloader selection
+BOOTLOADER = bootloadHID
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = lite     # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = no        # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = no         # Console for debug
+COMMAND_ENABLE = no         # Commands for debug and configuration
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
+BACKLIGHT_ENABLE = yes      # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
+WS2812_DRIVER = i2c
+
+# custom matrix setup
+CUSTOM_MATRIX = lite
+SRC += matrix.c
+QUANTUM_LIB_SRC += i2c_master.c
diff --git a/keyboards/spiderisland/split78/split78.c b/keyboards/spiderisland/split78/split78.c
new file mode 100644
index 0000000000..0301012749
--- /dev/null
+++ b/keyboards/spiderisland/split78/split78.c
@@ -0,0 +1,17 @@
+/* Copyright 2020 unrelenting.technology
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "split78.h"
diff --git a/keyboards/spiderisland/split78/split78.h b/keyboards/spiderisland/split78/split78.h
new file mode 100644
index 0000000000..2f6252f0c9
--- /dev/null
+++ b/keyboards/spiderisland/split78/split78.h
@@ -0,0 +1,36 @@
+/* Copyright 2020 unrelenting.technology
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "quantum.h"
+
+#define LAYOUT( \
+    l00,      l01, l02, l03, l04, l05, r00, r01, r02, r03, r04, r05, r06, \
+    l06, l07, l08, l09, l10, l11, l12, r07, r08, r09, r10, r11, r12, r13, \
+    l13, l14, l15, l16, l17, l18, r14, r15, r16, r17, r18, r19, r20, r21, \
+    l19, l20, l21, l22, l23, l24, r22, r23, r24, r25, r26, r27,      r28, \
+    l25,      l26, l27, l28, l29, l30, r29, r30, r31, r32, r33, r34, r35, \
+    l31, l32, l33, l34,      l35,      r36,      r37, r38, r39, r40, r41 \
+) { \
+    {   l00,   l06,   l13,   l19,   l25,   l31, KC_NO,   r00,   r07, r14, r22, r29, r21 },  \
+    {   l01,   l07,   l14,   l20,   l26,   l32, KC_NO,   r01,   r08, r15, r23, r30, r36 },  \
+    {   l02,   l08,   l15,   l21,   l27,   l33, KC_NO,   r02,   r09, r16, r24, r31, r37 },  \
+    {   l03,   l09,   l16,   l22,   l28,   l34, KC_NO,   r03,   r10, r17, r25, r32, r38 },  \
+    {   l04,   l10,   l17,   l23,   l29,   l35, KC_NO,   r04,   r11, r18, r27, r33, r39 },  \
+    {   l05,   l11,   l18,   l24,   l30,   l12, KC_NO,   r05,   r12, r19, r26, r34, r40 },  \
+    { KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO,   r06,   r13, r20, r28, r35, r41 },  \
+}