Eclogue 9 (Ecloga IX; Bucolica IX) is a pastoral poem by the Latin poet Virgil, one of his series of ten poems known as the Eclogues. This eclogue describes the meeting of two countrymen Lycidas and Moeris. Moeris has been turned out of his farm and is taking some kid goats to town for the new occupant; young Lycidas is astonished, for he had heard that Menalcas (i.e. Virgil) had secured the safety of the district by his poetry, but Moeris replies that, so far from that being so, he and Menalcas himself had barely escaped with their lives: they then proceed to recall passages of Menalcas' poetry. Lycidas wants to continue singing to lighten the journey but the distressed Moeris begs him to cease, promising that they will sing again when Menalcas returns.

In the symmetrical scheme of the Eclogues, this poem is the pair of Eclogue 1, which is also a dialogue about the land confiscations of 40 BC, contrasting the fate of a farmer who has been displaced with one who has been allowed to stay.

In the second distribution of Italian lands (BC 40), the city of Cremona, among other cities which had supported Brutus and Cassius in the civil war, was subject to confiscation of its farmland to settle veteran soldiers. In 40 BC, the task of distributing the land was given to Alfenus Varus, while Cornelius Gallus was in charge of taxing the northern Italian cities not affected by confiscation. It seems that the land of Cremona was insufficient, and that the confiscations were extended 15 miles into the land of Mantua, situated some 40 miles to the east of Cremona. A sentence from a speech of Cornelius Gallus is quoted by the ancient commentator Servius Auctus in which Gallus complains that, although ordered to leave three miles of land around Mantua, Varus had taken land almost up to the city walls.

The role of Virgil in this is not certain. It is thought that he championed the rights of the Mantuans who had lost their land, but he was clearly not entirely successful, since in Georgics 2.198 he states that Mantua unhappily had lost its land. Virgil is said to have come from the village of Andes (thought to be Pietole, 3 miles south-east of Mantua). As Wilkinson points out, we do not know if Virgil himself lost any land in the confiscation, or what the relationship was between himself (represented by "Menalcas" in this eclogue) and "Moeris". Menalcas, who is here referred to as an adept in song, has been identified as Virgil himself.

The general plan of the Eclogue is copied from the seventh Idyll of Theocritus, but with the situation reversed; for in Theocritus the speakers are on their way from town to the country, while in Virgil they are heading to town. Here and there in the eclogue parts of other Theocritus idylls are loosely translated, such as Idyll 3 (lines 23–25), Idyll 11 (lines 38–43), Idyll 14 (line 54) and Idyll 2 (lines 57–58).

As they walk to town, the youthful Lycidas and the older Moeris sing portions of four songs, all apparently composed by Menalcas (though some critics have suggested that the second pair are by Moeris and Lycidas themselves). Lycidas sings a three-line song, answered by Moeris with a three-line song; then Moeris sings a five-line song, answered by a five-line song sung by Lycidas. The two pairs exhibit parallelism, that is, each pair is a miniature example of amoebaean singing, of the kind found also in Eclogues 3, 5, 7, and 8. The first of each pair has a Theocritean theme, and in each case the answer has a Roman theme. It has also been argued that the two sung by Lycidas have an optimistic mood, expressing hope for the future, while the two sung by Moeris are pessimistic, expressing nostalgia for the past.

At this point Lycidas praises Moeris and asks him to continue. He declares that he too is a poet, although compared to the poets Varius and Cinna he is like a goose squawking amongst swans. (These words are adapted from Theocritus Idyll 7.37–41, in which the speaker compares himself to the poet Philitas as "a frog amongst crickets".)

After this Moeris complains that, because of his age, he can no longer remember the songs, and even his voice has given out. ("The wolves have seen Moeris first" – a saying explained by Pliny the Elder as warning that if a wolf sees you before you see it, you will be struck dumb). Lycidas replies that the wind has died down, and they have now reached the halfway point of the road, where a grove of trees surrounding a certain tomb will make a suitable place for a rest; or if Moeris is afraid they may not reach town before nightfall or be caught in the rain, Lycidas can help Moeris carry the kid goats while he and Moeris continue singing. But the unhappy Moeris begs him to stop singing and concentrate on their task, until such time as Menalcas will return.