diff --git a/src/Makefile.am b/src/Makefile.am
index 20a7d94fb01170c390ff1a6d23808a1b3be7ef2f..5cb1dc79ae68d65e22e35aef3a9ba9729981ccd1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -251,6 +251,7 @@ nobase_noinst_HEADERS = align.h approx_math.h atomic.h barrier.h cycle.h error.h
 		 chemistry/QLA/chemistry_iact.h \
 	         entropy_floor/none/entropy_floor.h \
                  entropy_floor/EAGLE/entropy_floor.h \
+                 entropy_floor/QLA/entropy_floor.h \
 		 tracers/none/tracers.h tracers/none/tracers_struct.h \
                  tracers/none/tracers_io.h \
 		 tracers/EAGLE/tracers.h tracers/EAGLE/tracers_struct.h \
diff --git a/src/entropy_floor.h b/src/entropy_floor.h
index 771bd098bc0bb8390da64bd7331404ad982f7d3b..0ecb137801725e0be3299e8d5801760bff35569c 100644
--- a/src/entropy_floor.h
+++ b/src/entropy_floor.h
@@ -40,8 +40,12 @@ static INLINE float hydro_get_comoving_density(const struct part *restrict p);
 /* Import the right entropy floor definition */
 #if defined(ENTROPY_FLOOR_NONE)
 #include "./entropy_floor/none/entropy_floor.h"
+#elif defined(ENTROPY_FLOOR_QLA)
+#include "./entropy_floor/QLA/entropy_floor.h"
 #elif defined(ENTROPY_FLOOR_EAGLE)
 #include "./entropy_floor/EAGLE/entropy_floor.h"
+#else
+#error "Invalid choice of entropy floor"
 #endif
 
 #endif /* SWIFT_ENTROPY_FLOOR_H */
diff --git a/src/entropy_floor/QLA/entropy_floor.h b/src/entropy_floor/QLA/entropy_floor.h
new file mode 100644
index 0000000000000000000000000000000000000000..4a124f31f4535f6f4fecfffbd90b4ae053020a8a
--- /dev/null
+++ b/src/entropy_floor/QLA/entropy_floor.h
@@ -0,0 +1,252 @@
+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2020 Matthieu Schaller (schaller@strw.leidenuniv.nl)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 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 Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#ifndef SWIFT_ENTROPY_FLOOR_QLA_H
+#define SWIFT_ENTROPY_FLOOR_QLA_H
+
+#include "adiabatic_index.h"
+#include "cosmology.h"
+#include "equation_of_state.h"
+#include "hydro.h"
+#include "hydro_properties.h"
+#include "parser.h"
+#include "units.h"
+
+/**
+ * @file src/entropy_floor/QLA/entropy_floor.h
+ * @brief Entropy floor used in the quick Lyman-alpha model
+ */
+
+/**
+ * @brief Properties of the entropy floor in the QLA model.
+ */
+struct entropy_floor_properties {
+
+  /*! Density threshold for the floor in Hydrogen atoms per cubic cm */
+  float density_threshold_H_p_cm3;
+
+  /*! Density threshold for the floor in internal units */
+  float density_threshold;
+
+  /*! Inverse of the density threshold for the floor in internal units */
+  float density_threshold_inv;
+
+  /*! Over-density threshold for the floor */
+  float over_density_threshold;
+
+  /*! Temperature of the floor at the density threshold in Kelvin */
+  float temperature_norm_K;
+
+  /*! Temperature of the floor at the density thresh. in internal units */
+  float temperature_norm;
+
+  /*! Pressure of the floor at the density thresh. in internal units */
+  float pressure_norm;
+};
+
+/**
+ * @brief Compute the entropy floor of a given #part.
+ *
+ * Note that the particle is not updated!!
+ *
+ * @param p The #part.
+ * @param cosmo The cosmological model.
+ * @param props The properties of the entropy floor.
+ */
+static INLINE float entropy_floor(
+    const struct part *p, const struct cosmology *cosmo,
+    const struct entropy_floor_properties *props) {
+
+  /* Comoving density in internal units */
+  const float rho_com = hydro_get_comoving_density(p);
+
+  /* Physical density in internal units */
+  const float rho_phys = hydro_get_physical_density(p, cosmo);
+
+  /* Mean baryon density in co-moving internal units for over-density condition
+   * (Recall cosmo->critical_density_0 is 0 in a non-cosmological run,
+   * making the over-density condition a no-op) */
+  const float rho_crit_0 = cosmo->critical_density_0;
+  const float rho_crit_baryon = cosmo->Omega_b * rho_crit_0;
+
+  /* Physical pressure */
+  float pressure = 0.f;
+
+  /* Are we in the regime of the equation of state? */
+  if ((rho_com >= rho_crit_baryon * props->over_density_threshold) &&
+      (rho_phys >= props->density_threshold)) {
+
+    const float pressure_floor =
+        props->pressure_norm * rho_phys * props->density_threshold_inv;
+
+    pressure = max(pressure, pressure_floor);
+  }
+
+  /* Convert to an entropy.
+   * (Recall that the entropy is the same in co-moving and phycial frames) */
+  return gas_entropy_from_pressure(rho_phys, pressure);
+}
+
+/**
+ * @brief Compute the temperature from the entropy floor for a given #part
+ *
+ * Calculate the EoS temperature, the particle is not updated.
+ * This is the temperature exactly corresponding to the imposed EoS shape.
+ * It only matches the entropy returned by the entropy_floor() function
+ * for a neutral gas with primoridal abundance.
+ *
+ * @param p The #part.
+ * @param cosmo The cosmological model.
+ * @param props The properties of the entropy floor.
+ */
+static INLINE float entropy_floor_temperature(
+    const struct part *p, const struct cosmology *cosmo,
+    const struct entropy_floor_properties *props) {
+
+  /* Comoving density in internal units */
+  const float rho_com = hydro_get_comoving_density(p);
+
+  /* Physical density in internal units */
+  const float rho_phys = hydro_get_physical_density(p, cosmo);
+
+  /* Mean baryon density in co-moving internal units for over-density condition
+   * (Recall cosmo->critical_density_0 is 0 in a non-cosmological run,
+   * making the over-density condition a no-op) */
+  const float rho_crit_0 = cosmo->critical_density_0;
+  const float rho_crit_baryon = cosmo->Omega_b * rho_crit_0;
+
+  /* Physical */
+  float temperature = 0.f;
+
+  /* Are we in the regime of the equation of state? */
+  if ((rho_com >= rho_crit_baryon * props->over_density_threshold) &&
+      (rho_phys >= props->density_threshold)) {
+
+    const float temperature_floor = props->temperature_norm;
+    temperature = max(temperature, temperature_floor);
+  }
+
+  return temperature;
+}
+
+/**
+ * @brief Initialise the entropy floor by reading the parameters and converting
+ * to internal units.
+ *
+ * The input temperatures and number densities are converted to entropy and
+ * density assuming a neutral gas of primoridal abundance.
+ *
+ * @param params The YAML parameter file.
+ * @param us The system of units used internally.
+ * @param phys_const The physical constants.
+ * @param hydro_props The propoerties of the hydro scheme.
+ * @param props The entropy floor properties to fill.
+ */
+static INLINE void entropy_floor_init(struct entropy_floor_properties *props,
+                                      const struct phys_const *phys_const,
+                                      const struct unit_system *us,
+                                      const struct hydro_props *hydro_props,
+                                      struct swift_params *params) {
+
+  /* Read the parameters in the units they are set */
+  props->density_threshold_H_p_cm3 = parser_get_param_float(
+      params, "QLAEntropyFloor:density_threshold_H_p_cm3");
+  props->over_density_threshold =
+      parser_get_param_float(params, "QLAEntropyFloor:over_density_threshold");
+  props->temperature_norm_K =
+      parser_get_param_float(params, "QLAEntropyFloor:temperature_norm_K");
+
+  /* Initial Hydrogen abundance (mass fraction) */
+  const double X_H = hydro_props->hydrogen_mass_fraction;
+
+  /* Now convert to internal units assuming primodial Hydrogen abundance */
+  props->temperature_norm =
+      props->temperature_norm_K /
+      units_cgs_conversion_factor(us, UNIT_CONV_TEMPERATURE);
+  props->density_threshold =
+      props->density_threshold_H_p_cm3 /
+      units_cgs_conversion_factor(us, UNIT_CONV_NUMBER_DENSITY) *
+      phys_const->const_proton_mass / X_H;
+
+  /* We assume neutral gas */
+  const float mean_molecular_weight = hydro_props->mu_neutral;
+
+  /* Get the common terms */
+  props->density_threshold_inv = 1.f / props->density_threshold;
+
+  /* P_norm = (k_B * T) / (m_p * mu) * rho_threshold */
+  props->pressure_norm =
+      ((phys_const->const_boltzmann_k * props->temperature_norm) /
+       (phys_const->const_proton_mass * mean_molecular_weight)) *
+      props->density_threshold;
+}
+
+/**
+ * @brief Print the properties of the entropy floor to stdout.
+ *
+ * @param props The entropy floor properties.
+ */
+static INLINE void entropy_floor_print(
+    const struct entropy_floor_properties *props) {
+
+  message("Entropy floor is 'Quick Lyman-alpha' with:");
+  message("Floor with slope n=%.3f at rho=%e (%e H/cm^3) and T=%.1f K", 1.f,
+          props->density_threshold, props->density_threshold_H_p_cm3,
+          props->temperature_norm);
+}
+
+#ifdef HAVE_HDF5
+
+/**
+ * @brief Writes the current model of entropy floor to the file
+ * @param h_grp The HDF5 group in which to write
+ */
+INLINE static void entropy_floor_write_flavour(hid_t h_grp) {
+
+  io_write_attribute_s(h_grp, "Entropy floor", "Quick Lyman-alpha");
+}
+#endif
+
+/**
+ * @brief Write an entropy floor struct to the given FILE as a stream of bytes.
+ *
+ * @param props the struct
+ * @param stream the file stream
+ */
+static INLINE void entropy_floor_struct_dump(
+    const struct entropy_floor_properties *props, FILE *stream) {
+
+  restart_write_blocks((void *)props, sizeof(struct entropy_floor_properties),
+                       1, stream, "entropy floor", "entropy floor properties");
+}
+
+/**
+ * @brief Restore a entropy floor struct from the given FILE as a stream of
+ * bytes.
+ *
+ * @param props the struct
+ * @param stream the file stream
+ */
+static INLINE void entropy_floor_struct_restore(
+    struct entropy_floor_properties *props, FILE *stream) {
+
+  restart_read_blocks((void *)props, sizeof(struct entropy_floor_properties), 1,
+                      stream, NULL, "entropy floor properties");
+}
+
+#endif /* SWIFT_ENTROPY_FLOOR_QLA_H */