Simone Cantarini or Simone da Pesaro, called il Pesarese was an Italian painter and etcher. He is mainly known for his history paintings and portraits executed in an original style, which united aspects of Bolognese classicism with a bold naturalism.

Cantarini was also a gifted etcher who achieved extraordinary delicacy and a vibrant and luminous quality in his graphic work.

Cantarini was born in Pesaro, now a town in the Italian region of the Marche, then part of the Papal States and ruled by the Della Rovere. He was baptized on 21 August 1612. His father Girolamo was a prominent merchant and the family was well-off.

There is no documentary information on Cantarini's early training. Initially he may have been a pupil of Giovanni Giacomo Pandolfi. A religious person from a church in Pesaro who supported Cantarini's artistic career accompanied the young artist on a trip to Venice. In Venice he could take advantage of the guidance of the Venetian late-Mannerist painter Sante Peranda and learned drawing skills from Francesco Mingucci, a fellow citizen of Pesaro residing in Venice. He returned to Pesaro. He received his first commissions from the Augustinian order in Pesaro and nearby Fano. His first commissions included the painting Saint Rita of Cascia, now in the Saint Augustine Church of Pesaro, and The Immaculate Conception with Saints (Pinacoteca Nazionale di Bologna).

It is assumed that Cantarini became a pupil of Claudio Ridolfi although the precise timing of the training is not known. Ridolfi would have passed on to him the Venetian style and a strong appreciation for the work of Federico Barocci, a collaborator of Ridolfi in Urbino. After Ridolfi left Pesaro in 1629 Cantarini was left without a teacher and was thus compelled to pursue his artistic training on his own.

As he was not tutored by a single master in his early years, Simone Cantarini was mostly self-taught and he absorbed the styles of other painters by making copies or sketches after their works. The prints by the Carracci together with the work of Federico Barocci were important influences on the young artist. He further drew inspiration from the caravaggesque art of Orazio Gentileschi, who worked in the Marche region during the 1610s, and of Giovanni Francesco Guerrieri from nearby Fossombrone.

Guido Reni was one of the painters whose work was present in various churches in the vicinity of Pesaro and Reni's mature style had an important influence on the young Cantarini. In particular, Catarini studied Guido Reni's Madonna and Child with Saints Thomas and Jerome that hung at the time in Pesaro Cathedral (now in the Pinacoteca Vaticana), and the Giving of the Keys to Saint Peter (1626, now in the Louvre, Paris) and the Annunciation (1620–21) that were in the church of San Pietro in Valle in nearby Fano. Cantarini started to receive commissions and one of his earliest masterpieces was the St Peter Healing the Lame Man, which was also placed in the church of San Pietro in Valle in Fano. This work reveals Reni's important influence.

Presumably around 1634 Cantarini joined Reni's studio, which was located in the via delle Pescherie near the piazza Maggiore in the old city centre of Bologna. Reni's studio was a form of boarding school and artist's studio. Reni considered Cantarini an experienced artist as he was soon allowed to stay on the principal floor of the house, which was reserved for Reni's more valued followers. Here he proved to be a student who had problems connecting with the other students and failed to attend classes such as the nude class, which brought him in conflict with the teacher of that class. During his stay in Reni' s studio Cantarini learned to etch and became very skilled in that technique.

Contemporary biographers describe a gradually deteriorating relationship between the master and pupil. The reasons for this are not entirely clear but have been attributed to Cantarini's inability to submit to the discipline of Reni's school and the fact that works of the pupil were sold with the signature of the master to increase their price. Cantarini further refused to engrave Guido's designs on the ground that his own works were as much worthy of publication. It is also possible that the pupil who had discovered the earlier masterpieces of Reni in the churches near his hometown was less impressed with the late style of Reni, which tended increasingly towards metaphysical visions populated with bloodless images. According to some stories the uneasy relationship between the two artists came to an explosive halt when Reni criticized a work of Cantarini in front of other students upon which Cantarini threw the painting against the wall. The break with Reni lead to a drought in new commissions, which forced Cantarini to leave Bologna.

Cantarini is recorded back in his native Pesaro in 1639. He is said to have had a relationship with a local young woman with whom he had extramarital children.

He made a brief trip to Rome in 1640 or 1641. After Reni's death in 1642, Cantarini returned to Bologna. Here he opened his own studio in the Palazzo Zambeccari, where he trained local artists such as Lorenzo Pasinelli, Flaminio Torre, Giulio Cesare Milani, Giovanni Peruzzini, Giovanni Maria Luffoli, and the engraver Girolamo Rossi. Giovanni Venanzi was also very likely his pupil.

In 1647 Cantarini was invited to Mantua by Carlo II Gonzaga of Nevers. Since it took him too long to finish the portrait the Duke had commissioned he was relieved of his duties. He became seriously ill and moved to Verona, where he died. Some biographers claim that Cantarini had created a scandal through his behavior and criticisms of the Gonzaga collection and it was suspected that he was poisoned by an angry rival.